Good point Phee, that Regina is emotional and Greg did literally burn any bridge there (with electricity!). I could see her wanting to kill him.
She completely relished telling Greg that she’d killed his dad, even gave him a little smirk right before she said he was dead. So yep, I’m pretty sure Regina is done with having any sort of sympathetic emotion towards Greg.
You know, it would be kind of funny if Hook ran over Greg with the JR (by accident upon entering NL), seeing as how Greg ran over Hook with his car.