Strange is working on taking the scarf further off and is about to start folding it up before Billie spins around, shoves her hand in his face, and pushes him backwards some. He stumbles, but manages to stay upright. He gives Billie a slightly indignant look before realizing that if he was close enough for her to shove her hand in her face like that, then he might have been too close.

Maybe. He's still not 100% certain he was too close.

"I'd need a proper knife first. After that, who knows?" They both know he wouldn't stab someone in the back, that's something which is blatantly obvious. There's a brief moment before Strange decides to talk a little bit of shop. "By the way, that teleportation magic of yours is impressive. Self-taught?"

Because he has a sneaky suspicion Billie didn't go to one of the magical universities like he did.