Markham watches as Renfrew tries to send another message, but there is noise in the background again.
Peterson learns that they haven't sent his message back yet, and he requests they don't send the message back at all, just to see what happens.
Both Markham and Renfrew disagree, since they aren't looking to create paradoxes here.
Peterson says they owe him one since he confirmed their success with his experiment. Markham agrees but reminds Peterson that it isn't a purely academic question; they don't know the consequences of not sending the message already received in the past.
Later, Peterson and Markham discuss the multi-universe theory, and this gives Markham an idea: Maybe the noise they are receiving in their experiment are tachyons, too—in other words, maybe they're also messages from others.
They isolate the signal and find it is too regular to be natural. They begin taking it down.
Markham goes on a walk, pondering the implications of their experiment and the paradoxes that might come with it. He knows the laws of physics must provide an answer, yet the ideas swarming in his head are too numerous for him at the moment.