Dug absolutely gave chase. It was another dog!!! - sort of, at any rate - and he had a ball and Dug was very excited and wanted to play.
This dog did not seem to be able to talk though, which was fine for Dug for the moment. Until he forgot about it and tried to talk again. Though he did wonder if it was just human-speak that this dog couldn't do. But before he could get much further than that with his thoughts, he was barreling down the hall after Tristan, his legs moving almost too fast for his body as he leaped and barked enthusiastically.
He was not thinking about all the sad people at the moment - he only had room for one thought. Get the ball away from Tristan so that he could make Tristan chase him instead. This was going to be a great game!
He skid a bit on the floor again, turning his head and trying to bite the ball from Tristan's mouth.