When Lapis told her story of how did she end up in a mirror, We see a big flash thing that might corrupted Remaining Gems because in The Return, Greg says something about Rose was only able to save a handful of her friends. Is he talking about that most of Crystal Gems become corrupted by a huge flash thing?
So what if The Diamond Authority use their big flash thing on Crystal Gem?
For example, Steven use his shield to protect himself from the flash but unfortunately the big flash got Garnet, Amethyst and Pearl and they turn into a corrupted gem and start to attack Steven.
What happens if your family suddenly attack you for real
They did attack Steven in Joy Ride but they thought he was Peridot! However because the flash thing got them, They will attack Steven for REAL!