He's worked with other units before. It wasn't common, sure, but it has happened. And every single time, they closed the case easily because they had double the help. Nothing went wrong.
But this time, everything went wrong. It had all gotten out of hand and a member of the other unit had lost their life. He knew how it was losing someone, after Haley of course, but the look of pure heartbreak and guilt on the unit's face was almost too much to bear.
You were the unit chief they were working with, and he wishes he never has to know how it feels to lose a member on the field. He just knows it probably felt suffocating, it probably felt like you were drowning in guilt and helplessness, even though it wasn't your fault.
Before returning to the BAU, he decides to give your office a visit. It doesn't look like he cares, he knows, but he truly does. He cares for you and your whole team more than he would admit.
Most of the desks were empty, people too depressed to come to work, but the desks that were filled all had different ways of dealing with grief. Some were angry, some were desperately trying to deny it and some looked like they had accepted it.
He knocked on your door and pushed in, seeing how you had stacks of work on your desk. Using work to help you forget and push the feeling to the back of your mind. He's seen it.
"Excuse me if I'm interrupting, I just wanted to check up on you.. your team seems to be in different stages of grief." He spoke softer than usual. It was a very delicate situation.
As you nodded in acknowledgement, he continued. ".. what stage are you in?" When you didn't respond, you were trying not to think about the grief, he slowly shut the door behind him.
"You're allowed to let yourself grieve, you know.. just because you're unit chief doesn't mean you're supposed to be the strong one."