Vash was next to the door, so the other him would have to go past him to leave, and he knew that Wolfwood would hate to see him go. But he also could see Vash's face, and he recognizes the determination there.

So instead of trying to stop him, as such, he does reach to hold the other one's shoulders. "Three is company. So we will be expecting yours again. All right?"

Take care of yourself. Soft. Hopeful. I'll do my best to take care of him.

Then he does stand aside, though one hand takes a little longer to drop from those shoulders.