[It would be a bad idea for Regulus to draw his wand for the same reason Remus decided not to cast a spell on him. A drying spell would have been easier, but it's too direct, and there's so much distrust between them even if they don't quite want each other dead that little gestures were better.. right?

He presses his lips together in a line, just for a moment, letting out a slow breath through his nose. If he has one thing in abundance, it's patience.]

It doesn't particularly matter to me, but Sirius might not be too happy if I leave his little brother out in the cold. Regardless of your opinion of him, and of me, at this point in time neither of us actually want you dead. I'd take advantage, if I were you.