Catrine goes in at 8, and the station is about a thirty minute drive from here. This means that Salem does not have a lot of time, made even worse when he realizes he doesn't work today. He won't have an excuse to be there.
Salem makes sure to not make Donny feel bad about this at all, he'd much rather the guy take care of his son than help him with this stuff anyway. This doesn't mean he isn't seriously stressing, however. He rushes through his morning routine and doesn't even put on his work uniform.
He doesn't work today, so it wouldn't really make sense, anyway. By the time he's heading down the stairs he is dressed in civilian clothes with his phone and keys in hand, nothing else. He plans on just rushing out the door, but is stopped when he hears a voice.
"Salem?"