The Chandler persona is right back in place; this time, though, it's the reflex not of social propriety (nor the amusement of earlier) but of self-defense. There's a subtle thread of unease that wasn't there before, though Sherlock may well be the only one to whom it's visible. Cal would hope.

Cal is good, but not perfect.

"Thanks, but we've got it," he says, relieving Sherlock of one of the boxes.