Need help with this room on extreme

Hey guys, I'm currently trying to finish the game on extreme difficulty for platinum. This room already humiliated me on normal difficulty. Now on extreme, it's my second day where I can't even make it to the second wave. I can't find a safe point in the room, I run out of ammo and die while trying to pick guns up, enemies sneak around me, kill me from behind and so on.

Anyone of you got a good guide or advice for a cheese spot inside the room? Otherwise I will quit the platinum run. I wanna play for fun, not for getting aggressive.