Single location as a pressure cooker

Give characters an exit and they'll use it. The single-location story takes the exit away and watches what's left.

That's the whole mechanism, and the greats run on it. Twelve jurors can't leave the room until they agree, so 12 Angry Men turns a slam-dunk verdict into a war of attrition. Rear Window pins you to one apartment with a man who can't walk, so every scare has to come to the window. Buried is ninety minutes in a coffin. None of these got confined because the budget ran out. The box is the point.

Confinement is a pressure system. When people can't leave, conflict can't be deferred. The thing they'd normally walk away from has to get dealt with here, now, in front of everyone.

What the room does for you

• It removes the cheapest out. "I'm leaving" stops being available. Whatever's wrong stays in the room.
• It forces proximity. People who'd never share space have to. The wrong two characters keep ending up at the same sink.
• It becomes a clock. A bounded space fills up. You feel it getting crowded, getting late, getting worse.
• It turns the set into a character. One room, described closely enough, starts to have a personality. It's seen things, and it keeps seeing them.

My test case

Potty Talk is two acts that never leave the men's bathroom of a packed, ill-kept club. Eight people, one night, no locks on the doors. The lock-less part matters. There's not even the illusion of privacy, so honesty becomes the last option left instead of a choice anyone makes freely.

The confinement is the hook, not a limit I worked around. Spread the same story across a whole night out, bar, sidewalk, cab, apartment, and the pressure leaks out every door. Keep them in the room and it has nowhere to go but up.

Stuck on something that feels diffuse? Try the brutal version: one room, no exits, and see what the story is actually made of. Related: schticks that stick.