A more perceptive person might have noticed that Isobel was clearly hiding something. A more forward person might have pursued this and demanded clarification. But Archer was content to take what she said at face value despite her fidgeting, busy-body behavior, and bright red cheeks. "I would say that it's a shame that you were so bored during this, but I believe that it may be a good thing." He'd have much rather told a boring story or two as opposed to revealing to two strangers and one test participant that he could turn invisible at will.
He took the tea and nodded at her invitation. "That sounds pleasant." As he started towards the living room, he paused, looking down at his cup. "Although it occurs to me that it's quite late." Honestly, he didn't want to go. Not really. But he had to be polite. "Please don't stay up late simply out of a formality."