Professor decides to go back for his rucksack. Stalker and Writer are worried he will get lost and die, but decide to press forward through the tunnel. They exit the tunnel and find Professor sitting on a rock, enjoying coffee and sandwiches.
The dry tunnel is not actually a dry tunnel.
Professor is a constant source of hilarious situation. But his most hilarious moment is when he's ranting at the stalker when they approach the Room... a phone near them starts ringing, professor denies the call and continues shouting at his now-totally-shocked companions. Only several seconds later he also realizes this phone is in the abandoned building several kilometers into the zone, with everything completely wiped out. Followed by his Crowning Moment of Awesome, when he decides to make a call.
Occasionally, the AI will lose the squad-based tactics routines and you can wipe out entire squads by standing inside a building with a shotgun and killing them one at a time as they run in the door. Bodies can pile up just inside the doorway, and those remaining outside will immediately conclude that the best course of action is to run in like the last twenty guys did.
Similar hilarity will ensue if you find a couple of bandits or expendable Loners (if you're feeling cruel) inside a building and have a spare rifle grenade (or an RPG, if you're feeling extraordinarily wasteful). If you're very very lucky, not only will the men inside be killed (instead of relatively unharmed and pissed off at you) but one or two will be in hilarious positions, such as being partially glitched headfirst through a wall with his hindquarters hanging out.
The PA announcements at the Freedom base in Clear Sky will occasionally be interrupted by arguments between the camp trader, Ashot, and the technician, Yar. Listen for yourselves.