It happened towards the beginning of the game when you first get Ellie and you're going through that building with the Clickers and shyt, and there's a safe in there that you need a combo to. I know that's a vague ass description, lol. But, that's the best I can do. She ran around the corner from where the safe was and one grabbed her or something and she started bussing. I don't have "footage," of it, but I didn't imagine it happened either. You can believe me or not, it's cool either way, breh.