It has been a long day for everyone, even someone with a service record like the Master Chief's, and he's finally managed to work off his nervous energy. He didn't relax after coming back from Cargg, he's used to a fight like that being the prelude to days of the same. It's hard to turn it off, especially with how worried he is about the rest of the team. Cortana in particular.

It took a lot of running to wear himself down, a lot, but he's finally returned to his quarters and showered and eaten. He's managed to reach a place where he can sit down and sort out his comm without itching to move.

It's not an ideal solution, but it's what the Chief has. Maybe tomorrow will be a better day.