Well, I've written myself into a corner again...

[Barracuda]

Smoking the bugs out of the hallway is another idea. In fact, if your character can find some vinegar, they will have everything they need to make chlorine gas and eliminate the bugs that way. Maybe find a balloon or something that will burst on impact (like a glass bottle) put bleach and vinegar in it, shake vigorously, throw, and run like hell? That would kill the bugs.

[Ironclad Alibi]

And lingering traces of the chlorine gas might provide a plot point later on in the story.

[Mytical]

Smoking the bugs out of the hallway is another idea. In fact, if your character can find some vinegar, they will have everything they need to make chlorine gas and eliminate the bugs that way. Maybe find a balloon or something that will burst on impact (like a glass bottle) put bleach and vinegar in it, shake vigorously, throw, and run like hell? That would kill the bugs.

This was going to be my suggestion as well...BUT I would also advise the following. 1st find a dead body (this will come in handy in a minute). Find bleach and ammonia of some sort. Get a towel, in fact a couple of them. Push body out, let bugs draw near. Mix the bleach and ammonia. Throw it out the door. Slam the door, put towels under the door. Put a single towel or bedsheet over mouth and nose. Wait. Fumes will disperse soon enough, dead bugs, hero can get to room. IF any bugs are left, throw dead body, distract the remaining bugs, get in room.