If it's rude to lean against Breakdown, it probably doesn't register as rude after the time he's spent with Sam. She's leaned on him, sworn at him, climbed on him---a very little---threatened him a time or two, and kicked him the once, so Will's remarkably well-behaved in comparison. Rather than be a bad influence, the skin-witch followed suit, one hand against Breakdown's side, the other planted on her hip as she considered the boy; Breakdown's answer got an acknowledging nod (which she was sure he'd see, somehow) but no more.
breakdown vs xenomorph queen let's go
“Why d'you ask?”