It's obvious that there's some big internal monologue going on in Strange's brain as he just continues to stare at Lambert like a goddamn creep. After Lambert drops the blanket, Strange snuffs out his fire and reaches over to grab Lambert's arm.

"We should leave Rita and Herbert to their work. Can we have a word in private?"

Should he make contact, he'll dig his claws into Lambert's arm hard enough to possibly draw blood.