An area is exploding and falling apart, because a timed explosive has been set. Even though that explosive hasn't gone off yet, it's causing the rest of the area to blow up as well.
This combines for Rule of Drama two things that you'd logically expect to be mutually exclusive: the Exact Time to Failure of a carefully planned detonation people are intended to escape from, with the Stuff Blowing Up of an out-of-control chain reaction or random system failure. It can also be seen as a justified variation on Outrun the Fireball — much more plausible to run away from a succession of small explosions than a single huge one.
The bomb is usually on a short fuse. If the bomb dooms the villain, a Catastrophic Countdown ties in naturally with a Collapsing Lair. While this trope usually serves the need to make the danger a bit more visible, it is not unreasonable for a Self-Destruct Mechanism to destabilize before it obliterates.
You have two minutes to read examples of this trope!
- Captain America: The First Avenger has the Italian HYDRA Base undergoing several minor explosions before resuming the rest of the self-destruction protocol related explosions. Justified, as Zola briefly interrupted Red Skull while he was arming the self-destruct protocol when shocked that he's blowing up the base before Red Skull calmly informs Zola that "Our forces are outmatched" while pointing to a video screen of Captain America fighting the forces and then resumes inputting the self-destruct protocols.
- In Aliens, the mining facility where the action is set begins to fall apart several minutes before the 19-minute countdown given by Bishop until the reactor's failure. In this case, there is overlap with Excessive Steam Syndrome as well. Justified as the reactor is breaking down as it's overheating — the countdown is simply a warning to get to a safe distance before the reactor goes critical.
- Metroid is a bit of an interesting case. While the NES original completely averts the trope after defeating Mother Brain, the GBA remake Metroid: Zero Mission barely offers an appropriate retcon for playing it straight in the same place. However, Zero Mission does avert the trope later on in the Space Pirate mothership.
- Super Metroid plays it straight twice. When Ridley escapes the space colony in the beginning, an announcement claims that the colony's self-destruct has been activated, urging immediate evacuation. Naturally, the whole place starts shaking, steaming, blowing up, and even rocking back and forth quite impressively. Later, at the end of the game, the entire planet starts exploding and flooding with acid, because a "Time Bomb has been activated".
- Averted in the final escape sequence of Metroid Fusion. While there is some destruction near the exit of the ship, that's due to the Post-Final Boss rampaging about.
- Metroid: Other M as well. An AI voice announces over an intercom that a self-destruct sequence will detonate in about five or so minutes. For some reason, your escape becomes riddled with burning debris and wreckage.
- Metroid Dread: Hanubia sector is on fire and crumbling in places after Samus downs the Itorash with Raven Beak in it, and kills the latter down to the last X cell. She has three minutes to get off of Planet ZDR before it explodes, killing her and all the X Parasites on the planet.
- Star Fox 64: During the Fortuna mission, Slippy notices several enemy craft leaving the captured base. ROB 64 informs the team that the enemy planted a bomb in the base; before anyone can defuse it, they must deal with an attack by Star Wolf. If you drag out the battle, you'll notice the base starting to spark and billow forth a few small explosions. When your time gets really low, the original stage music will start up again, timed so that the climax of the track will play while everybody retreats.
- Halo: Combat Evolved: The Chief destroys the Halo ring by detonating the engines of the UNSC Pillar Of Autumn. After frag blasting the vent core, Cortana puts a timer on the Chiefs HUD counting down the engines going critical. Despite apparently driving the length of the ship going away from the engines, various fires and explosions can be seen all through the Trench Run. Possibly justified as collateral damage from the Enemy Civil War going on all around you as the Covenant fight off the Flood while racing to escape themselves.
- Halo 3 has a variant of this. After starting up the Halo ring, it needs several minutes to charge and literally shakes itself apart. The last section of the game is a mad dash to find a way off. While there's no explicit timer, the structural plates fall off at a constant rate. Justified in that the thing was half-built when it was fired (it was a replacement for the one blown up in the first game).
- In the Sega Genesis video game X Men Clone Wars, destroying the Sentinel activates the self-destruct function of the entire Sentinel factory... and hundreds of smaller, random explosions prior to the one that actually destroys the factory.
- Descent and its sequels. When you shoot the reactor in any of the mines, a voice announces a Self Destruct Sequence, and you have about one minute to get to the exit before the entire complex goes nuclear. For no apparent reason, during this minute the screen shakes uncontrollably while lights flash and sirens roar.
- Overload does things much the same as Descent, where a reactor or boss will cause the facility to enter a self-destruct sequence when they are destroyed, but doesn't give any leeway in the countdown.
- A countdown isn't actually seen in Rebel Strike, but the trope is present in spirit in the climax where Han Solo has to escape from the self-destructing Endor shield generator Bunker while fighting against Sarkli before the base completely self-destructs.
- In Medal of Honor: Allied Assault, after planting the bombs, Fort Schmerzen is rocked by explosions that you have to stay ahead of as you race for the exit, although it doesn't completely explode until you get out.
- The laboratory self destruct mechanisms in the Resident Evil series do this. As an aversion, the self destruct sequence in the original the first one in Code Veronica has no destruction or tremors until the countdown expired or you finished the escape.
- The Moon Transmitter in Beyond Good & Evil is rocked by tremors and explosions during the self-destruct countdown.
- The Legend of Zelda:
- The Legend of Zelda: Ocarina of Time features a sequence where Zelda informs you that Ganondorf's castle is collapsing and they must escape within three minutes. Justified in that said castle is upheld by magic, which would be fading after Ganondorf's defeat. (That, and Ganondorf is deliberately trying to bring the castle down on you in a Taking You with Me attempt.)
- The Legend of Zelda: Majora's Mask has a downplayed version on the last day before the moon crashes onto Termina. The ground repeatedly shakes, presumably due to tidal forces, but nothing actually blows up until the impact.
- Turok: Evolution has a huge city suspended above a canyon with giant tethers. At one point, you must destroy the city by releasing the tethers, sending it crashing down to the canyon floor. Once the tether release consoles are activated, the countdown begins, and the city begins to collapse around you, along with lots of tremors. All of this WOULD make perfect sense, if it weren't for the fact that only when you finally DO escape, do the tethers actually detach from the canyon walls.
- Dino Crisis:
- Dino Crisis 2 plays it straight with facility at the end. There is a large tremor just as the self destruct countdown begins, and then in the final FMV everything begins to blow towards the end of the countdown.
- Dino Crisis 3 does it twice. The first time is justified, as the Ozymandias's primary power core has gone into critical overload and everything is shaking apart as a result, though this part strangely lacks a countdown. The second time however plays it straight, as soon as the self-destruct countdown begins, the ship starts shaking violently every few seconds, and on your way to the escape shuttle there are explosions and falling debris. The following FMV shows the interior of the ship collapsing spectacularly as the ship's computer counts down the last 10 seconds.
- Pony Island: Initiated by the player, when they commence a full system dump. The lost souls, in the vessels of ponies, have to all race to stay ahead of the destruction of Lucifer's machine... they don't all make it.
- Resident Evil Abridged: After Chris defeats the Tyrant, Rebecca sets off the Umbrella lab's self-destruct sequence, giving the surviving S.T.A.R.S. members 4min. to evacuate. But as they near the helipad, another wave of B.O.Wsnote attacks. Jill and Rebecca hold them off while Chris signals Brad, then defeats the Tyrant a second time. They escape only moments before the Umbrella lab's destruction, which takes the Spencer Mansion along with it.