Nice!, I can see you put alot of effort into this. I think the atmosphere is great, definitely gets across the idea of claustrophobia and anxiety. My thing with voice acting is that more often than not it detracts from the game unless done well and yours was done well so good job!
My one big critique would be that everything you did could have been done on a level twice as small, by spreading it all out so much (in my opinion) the atmosphere I described above tends to dissipate a bit and isn't as effective. What that did for me, atleast, is not make it as exciting to be running around, putting out fire and getting victims to the exit; I'm sure if the gamefield was smaller it would have been much more tense (just my opinion though).
Overall though great game and innovative concept!