Blackjack's sword can destroy soul jars. Rampage is immortal because she has a healing talisman as a soul jar. Rampage wants to die. Why doesn't she just stab herself with Blackjack's sword?
It was established both in the mainstream show and Fo E that only a cockatrice can dispel its petrification spell, and killing it will just doom its victims to be petrified forever. But when Blackjack kills Gorgon, his victims are restored. Why?
Possibly because he's only half cockatrice, but it's still pretty odd. Are you sure this was established in the show? I've seen plenty of fan stuff contradicting that.
Well, at least in "Fallout: Equestria" it definitely was like that.
Perhaps this is actually a bit of Fridge Brilliance, given his personality, he probably released them all as his last act.
I think he has to be looking at them for that to work.
He had a lot of magic; when he turned ponies to stone, they writhed in agony, but in the show, a regular cockatrice turned Fluttershy (partially) to stone and she didn't seem physically hurt at all during or after the process. Maybe he had enough magic to turn them back without looking at them.
I can't remember if this was true in the original Fallout Equestria, but in Project Horizons a pony that loses its soul enters a coma. An upload without a soul acts noticeably different from a living pony, but is clearly not in a coma. Why does uploading and removing the soul do less damage than just removing the soul?