Animals vanish through airlocks

I lost a Puft to this. I was trying to trap it but still have access to the Slime without having to make a U-bend water tunnel and apparently it can open doors on its own. The door closed on top of it and it died. RIP Jerry. :'(

 

This explains why my Pufts dissapeared Happened to 3 in a single game.

It doesn't happen all the time, so I don't think it's how it's supposed to work, but it's a bug. I found 2 Pufts in one "hole". One just disappeared before my duplicants even got near them, no idea what happened to that guy. The second Puft once stood in the door, door closed on it, and it vanished. I loaded in the previous day, when it was still alive, and since then it stood right in the door while my duplicants were moving in and out, with the door closing on it and it's fine. It happened 4 separate times and it didn't die.