It seems a little backwards to run into NYC, since that is the NEXUS of where "superhero adults" are, SHRA or not, who'd want to capture them and get them back to foster care (if not a Fed Detention Center awaiting N-Zone jail placement). They've also been trying to clean up the mess in CA's crime areas after they beat The Pride, so something would have to be a bit climatic to get them to flee the Hostel.
I do agree that RUNAWAYS, like any good team book, is about the ensamble cast even if one does have favorite characters. Hence why I really don't want Vaughan to off another one before he leaves the book. I mean if Whedon offs someone we can all ease ourselves by calling him a "hack" with other people's creations, but when Vaughan does it, these ARE his creations so he has total right to do so. After Chase, Victor would amazingly be my next fave, then Karolina, Molly, Nico, and Xavin. But I even do like Xavin; Zeb Wells used him very well. Victor is usually more reasonable and less vindictive compared to the other Runaways (who sternly don't trust any adult), although that may change dramatically with Chase now threatening Nico.
To me, whenever the RUNAWAYS seem betrayed from within, there is no forgiveness. They hated their parents and offed them. Alex betrayed them and he died, with most of the other Runaways a little miffed that Nico even bothered to try to resurrect him (BTW, 3 to 1 odds Whedon brings back Alex and says, "Oh, you did resurrect me, I just hid" within a year). Topher naturally got dusted in vol. 1. My point being is that usually these things follow a pattern, and so one would EXPECT Chase to end up getting murdered fighting the team now. Which may mean that may not go down. Eventually these kids are going to have to learn how to forgive, that you can't simply waste all your enemies or expect them to conviently die off.
A cop-out answer could be that using "The Staff of One" may have "corrupted" Chase even more, like Gollum and the One Ring, but I sort of doubt Vaughan would go there (even if it would make "East Coast/West Coast" more relevent). The more expected path is that Chase is just doing exactly what he hinted; Gert was the one who kept him in line and "out of the dark side", and without her, he's fallen back into older, more corrupt ways. Naturally, the irony here is that if he did revive Gert by killing Nico, Gert would never forgive him and might possibly want him dead herself.