Pia is immediately aware that Marcus doesn’t want Skitter for innocent reasons; she realizes she’s a target. As far as Marcus and his cronies are concerned, Skitter getting run over is an exciting turn of events. But Skitter is one of the things that connected Pia to Santi. Skitter also allowed Pia to feel like she could advocate for herself and yell at people—now, she’s silenced. And this whole incident recalls how Santi was killed, which makes it even more traumatic for Pia. Boys, she’s seen, are jealous and petty, and they don’t think of how it might affect others when they do something like push a girl. This can be deadly, as Pia knows all too well. Stevie is, in Pia’s mind, guilty by association, which is why she runs from him. She has no reason to trust that he won’t try to hurt her even more.