Nathan did try to keep himself busy during the day. He'd set his sights, for awhile, on being on a Quidditch team. He couldn't now, but that didn't keep him from making up his own regimen to keep, just like he would if he were actually in training. That meant working out several days a week, at the very least.
It also served as a good outlet for tension and aggression and for burning time he didn't know what else he'd do with.
He was surprised to see Mandy at this time of day. He blinked and then smiled, happy as always to see her. "Mandy! I didn't expect you here until later. No, no, your company is always welcome."
He pulled off one of his gloves, not big bulky ones but ones that did offer some protection, partly magical, to his hands. PUshing his sweaty hair back, he smiled again as he looked her over. "Special occasion?" he drawled.