He nods again, all his attention focused on the older man. Tactically, this is an incredibly bad decision and Tadashi knows it, but he's not going to give Callaghan any more reasons to rethink his choice.

"I understand, Professor. Really."

He sounds sincere enough and, as an afterthought, he pulls his phone back out, tapping the screen maybe half a dozen times before quickly pocketing it again. Callaghan's phone should be going off shortly. A number with a nearly empty message attached. Just a few periods to fulfill the content requirements.

"In case you need something."