The only reason Doc hasn't slinked off to the other room to go through the clothes there is because it seemed childish to do so, like it's making some sort of statement that they can't even work together. He can be the bigger man here. He always has been, or has tried to be anyway, around other people. Negan ought to be no different.

He opens the adjacent wardrobe door and takes in a deep breath, letting it out slow. His eyes glaze over the too many clothes on the hangers, still not accustomed enough to fast fashion to get used to all this excess, and probably taking too much time going through each item compared to Negan who seems far better at picking over things quicker. Probably on account of him having more experience doing so.