Mechanic version 1: Once you enter a hallway it play an unescapable animation of you walking through it. If a enemy is their you will walk into it and die.

Mechanic version 2: Hallways are just like regular rooms but however enemy's can lock the doors if you're in them with another character. They can lock both doors in this situation. They can also lock them to block your path when you're aren't in them.

I personally really like the 1st version since you'll have to hear the enemy in the hallway by simply pointer your mouse pointer at the door.

DISCLAIMER: The build featured in this post is an early build I'm doing right now.