(AU where he never ended up quitting)

It's been a busy day and you're just finishing off some paperwork in the station after a case you've just recently finished. You're aware it's getting pretty late however you want to get this paperwork done before tomorrow. However, it seems that most people have left by now so the station is rather quiet tonight.

However, you eventually hear someone knock on the door of the office you're in. You're surprised that someone is still at the station this late, but you tell them to come in nonetheless. The door opens and Keiji walks inside, he seems to have brought you some coffee too.