stuck in black plague - after machine room

[zozza2001]

I'm stuck in the black plague. I have turned the valve and fixed the gas leak but don't know where to go now. There is a dead man in the corridor now as I come out of the machine room and another locker room has opened where I got batteries and a flare - but that's it....don't know where to go from here.....been wandering around for ages....

I have obviously missed something but can't figure it out

help!