(please enjoy this video I took a few weeks ago- where do you think he learned to get the truck un-stuck with his foot? Sometimes he is just hilarious)
Apparently this is how Nolan 'takes it easy' by keeping his running around like a maniac to only one room. Clearly he seems fine but if your volume is up you can hear him breathing in the later part of the video. I think he likes that sound and is trying to get his throat to make that sound. I don't love it.