Someone has to. There may not yet be any proof that Stane is the one trying to have Tony killed, but as far as Cal is concerned, that doesn't make it any less true. Peter believes it, Sherlock suspects it, and that's more than good enough for Cal.

He smiles slightly.

"You'd be surprised how often it comes in handy."

One of the staff members, Danielle, steps out onto the porch and silently puts down Cal's cigarettes and lighter. (Peter has no ethical or moral qualms whatsoever about encouraging a tobacco habit in place of the marijuana one. Whatever gets the job done.) Cal mouths a thank-you to her and lights up with relief.