To add to what @myscrnnm said, when resting in your room, use the toilet and that will give you these tubes of stuff in your private locker that can be used to kill the BTs. Just take the tubes out of your locker with your gear before you head out. Then when you are trapped by BT's, equip a tube and toss it at them to kill them. I want to say the tubes are called ED-2 (I may be misremembering here).Lol, didn't even realize I did that. I like it but so far I'm really confused what I'm supposed to be doing when I encounter BT's.