Eh, Gren's never served time. Sure maybe that might do something to improve his street cred, but he's a little too clever to let himself get caught for the sake of intimidation. Besides that, he wouldn't consider Laura a threat in a practical sense. Unless she tries to kill him or anyone else he is friends or in the process of befriending, she is, at worse, an annoyance. I can see tension, but I don't suspect violence.