The hero is alone in a Die Hard situation (with limited resources and running low on ammunition). He manages to free one or more hostages, and the first thing he does is to give away his only gun to one of them.
This may happen for several reasons. Possibly the rescuer is soon going to acquire another one himself. (You'd think, though, that in that situation, it would be better to wait until you actually had a second gun.) Possibly the rescuee is better trained to handle the weapon. Sometimes, however, it happens for absolutely no reason, other than to be dramatic and make things tougher for the hero and/or show what a good guy the hero is.
Note that this is completely different from any occasion where someone on a rescue mission gives a hostage a spare gun, as happens in Die Hard (which would have been a subversion anyway, as he deliberately gave the Big Bad an empty gun) and near the start of Mission: Impossible III. This just makes good sense that both you and your ally/friend are armed while trying to escape.
In Real Life, it is worth noting that (in the highly unlikely event you find yourself disrupting a hostage situation) this is probably a good idea ONLY if the person you are giving the weapon to is better trained to use it than you are. It is also worth noting that a police officer or soldier who hands their government-issued weapon to a civilian stands a very good chance of being punished for breaking regulations.
Examples:
- In the movie Air Force One, when James Marshall (Harrison Ford) frees the staff from a locked room aboard the aeroplane, the first thing he does is give his gun to the Secret Service man, which makes tremendous sense, regardless of his President Action abilities.
- Non-gun example: in the Lone Wolf book Fire on the Water, if you have the Magic Spear (the only weapon at that point that can harm a Helghast) you can give it to Lord-Lieutenant Rhygar so that he can guard the entrance of the Tarnalin tunnel. In early editions, you get killed for doing this.
- In the Stargate SG-1 episode "Foothold", as soon as Jack O'Neill frees Major Davis, he gives him his pistol.
- Deus Ex
- After you free Agent Gunter, you have the option of giving him your pistol.
- A player who isn't careful with their weapons can find themselves in this situation in Deus Ex: Human Revolution before the first shootout with Belltower in the Alice Garden Pods, as Arie Van Bruggen begs for a weapon to defend himself. And if you don't give him one, he will die. Of course, depending on Adam's augmentations, a gun may not even be remotely necessary to escape unharmed, ultimately subverting the spirit of this trope.
- On the other hand, if you didn't know this was coming and didn't have a spare gun you picked up on the way, giving him one of your weapons means giving away a substantial investment of weapons mods that you're not going to get back.
- In Dead Rising, in general it's better to give your guns to the non-suicidal survivors you rescue because as NPCs they will have unlimited ammo. As an added bonus, since bosses tend to go for you first, doing so frees the survivors to pepper them with bullets.
- Silent Hill: For no apparent reason, police officer Cybil Bennet gives her pistol to the protagonist Harry Mason, an untrained novelist. She appears armed in other situations without Harry giving it back, so it may have been her backup handgun.