Eventually, Cal did decide it was best to leave Tony and Sherlock to themselves; he got up, touched Tony's shoulder, muttered something about being downstairs, and went.

He's still there. He called Tina at one point, to have a vague conversation where she tried to console him despite the fact that he couldn't tell her what he was upset about - it wasn't his place to say anything, he explained, and she understood.

After that, he raided the kitchen.

But mostly, he's been in the living room, flipping silently and pointlessly through the TV channels and waiting to see if he would be needed.