In response to /post/124538116014/in-a6a6i5-around-there-john-jumps-through-time, The only person who was prevented from being killed was Vriska due to Terezi having captured Gamzee, which lead to her not going and killing Vriska, which is why she is still alive in the retcon. I saw a lot of confusion about this when those upd8s were released.