Stuck in dog kennel area (black plague)

[GraphicsKid]

So I've just reached this part where I've just shut off the lights, and I'm trying to go back down the hall, it stops me, says "there's something crawling in the walls" or something to that effect, and no matter what I do, I get to a certain point down the hall and something bits me twice and kills me... but I can't see it at all, and I can't outrun it. I can't figure out what I'm supposed to do here.