Keenly aware though he is, Severus is, for a time, lost in thought taking stock of newly appeared chemistry equipment; much of it crosses over with things he can use for potion-making. The clink of glass and the rapid train of his thought process obscure precise footsteps, though he's aware of someone approaching him. A beaker is set on a shelf directly over Hi, and Severus registers female, and familiar, and given routine and timing--

"Going to make good on those threats, Ms Bennet? --Fuck."

He turns his head on Bennet and the tone of voice he was using (one definitely not suited to a sisterly friend) immediately aborts into one of moderate panic. His face goes a bit red and he snaps his head back towards the lab equipment, litany of swear words continuing silently. "Sorry. Hi. Lily."

KILL ME NOW is basically blinking over his head in neon lights, oh my wizard god.