It was mostly just wanting to get there before the food got cold, and the ability to hold people to promises OR ELSE. But it still counted since he didn't want to be rude.

Once they reached the bathroom, and after checking that no one would see, he pushed the door open, revealing a portal to his apartment. When he stepped through, just for an instant, Knuckles could see through the mask that there was a lot more fabric to Cole.

Then he was through and normal again, motioning that he come through too.