Where the hell did yara come from lol!!

Hey, I'm replaying TLOU2 for the 3rd time (trying to get its platinum trophy), and I just finished the sniper part (Tommy), and I was wondering—where the hell did Yara come from? Because we left her back… Yeah, she might have flanked him, but STILL—how did she reach us just in time in a few seconds?! Is she the Flash or something? lol

Man, Abby's plot armor is insane ( And I don't hate her as a character btw)