>It shows that the facility has the power to ressurect things several times.
Or they were never dead in the first place.
Ruby never necessarily "DIED", Ace could have just filed her as dead to make her a subject of his cruel experiments, and just because the bear zombie appears half-melted doesn't mean it's not still alive.
The only ones that seemed to COMPLETELY die are Red and the Hound zombie, and both of them haven't come back yet.
My theory: Ace is the BBEG here. Whether he was in charge or just another one of the doctors here, he began filing people as 'dead' and stashing them away in his private lab to do horrible experiments on them.
It would explain Red's whole NEVER CATCH ME NEVER NEVER NEVER thing: he'd rather die than be caught by Ace and taken back to the experimenting table.
Combination experiments, drugs, and head trauma would explain Ruby's hallucinations AND amnesia, as well. Her "visions" could be MEMORIES, like when she saw herself dead in the crate, it was a flashback to her near-death experience inside that very crate, where Red stashed her for whatever reason (perhaps Red was acting kindly after all, and he was trying to spare her the cruelty of Ace's dissection table)!