Indeed, to Ren, the djinn did meet most of the criteria.
With all the djinn's bodies down below, he could have, just like Ren, used the chaos to hide and enter the vault.
For all Ren could have known, the djinn could have just been faking death and then used the moment when Ren and Lily weren't paying attention to sneak into the vault.
There were hundreds of corpses down there; even with his enhanced eyesight, Ren wouldn't have noticed an alive one.
Scratching his head, Ren, trying to comprehend Ruby's leap in logic, questioned.
"So assuming this djinn is the intruder...you're saying that he made this space far earlier than I sent the purple orb."
Nodding her head in agreement, Ruby stood back up before replying.
"There was definitely time."
"Those two recruiters that you saw earlier in the vault weren't there at the start."
