Enemies stay dead

So I am making a house and I want where you go from the hallway to the bedroom. You then grab a key to unlock the next room in which then you have go back to hallway to use key. so in hallway there is mobs and when I kill them and go bedroom and then back to the hallway they are back alive again. how do I kill them and keep them dead?
Game Link: https://flowlab.io/game/play/1473368


edited game link in it


when you leave the room it should tp you to a new level that looks exactly the same but with either stationary dead mobs or no mobs at all

if you are on free edition I have away that you don’t need to make a new level to do it (if you need that way just message me)

Yes I am on free way and okay ty!!!