There's a moment where Vash pauses on his way back. That overwhelming feeling that he's making everything worse taking it over.

Hypocrite. Nothing but a murderer and hypocrite. You always ruin everything. Liar.

Perhaps Cyril and Knives will feel it. The quivering edge of panic of a Plant feeling overwhelmed. It's just for a moment while he's alone on the walk back. Then it's gone again. Vash refusing to sprial where his kids may feel his emotions.

Vash is nothing but smiles and neutral feelings once more by the time he enters the cabin.

"Heh, liking the idea of being called Uncle?"