User blog comment:Factual Frost/Questions about Killer Queen/@comment-4959537-20171025051932

1) It's clear that Kira was controlling the air bombs directly, as shown when Josuke started giving him directions after taking the phone from Yoshihiro, I think it's implied that Kira has some limited control over the things he turns into bombs or maybe could be something that only happens with the air bombs.

2) Actually this is directly explained in the manga, but the anime skiped this part.

Basically, in the end of the Super Fly fight, when Josuke beats up the guy, he grabs the tower to not fall, but then the guy starts bleeding into him to make him slip, so Josuke explains that after the blood leaves a body, somehow isn't considered more as a part of the whole body, so he can't heal him to save himself, but the mass of blood itself counts like a whole, that's where he got the idea to use his blood in the final fight, as even if he can't heal himself with Crazy Diamond, after the blood leaves his body, it doesn't count like a part of him, so the blood would try to return to the nearest mass, in that case, the blood on Kira's jacket that he splattered all over him with the blood blade.

3) He never implanted Bites the Dust on the nurse, BtD is automatic, but he has to activate manually like his other bombs, at least in the first loop, remember the first time when he activated it, Hayato was dead, but then Kira was stabbed by the arrow forcing the ability to activate for the first time, everything looped back in time and Hayato was alive and already had BtD on himself.

The limit he says is just a figure of speech I think.