"If you can possibly do elemental magic all on your own then I think you have proved that magic has a use for someone like you."

Notice that insistence on the correct word. Viktor did take the bathrobe but once he had put it on, K was already gathering the discarded pieces of clothing on the floor. Before he put the dirty blanket over one arm, one of Viktor's hands took one of his and the other hand was clinging to K's wrist.

"Can I... Can I stay with you? Even if you are just going to do laundry."

Much as he wants to find a solution to K being possibly threatened by void magic, he still feels desperately vulnerable. K might end up with a clingy Viktor shadow.