Loki was not familiar with this 'Shakespeare', which Dr Strange quoted, but assumed it was some mortal philosopher and so Edna began to shake her head knowingly, until his eyes met the sorcerer's. Loki was the strong impression that Dr Strange could see through his ruse. For a moment, Loki simply stared, but then smiled: so long as he didn't confront him directly, he wasn't going to drop his disguise.
"And what sort of recourse would you take against these beings, should they cause trouble?" Edna said, slyly, almost tipping her hand.