Tamed pet rats tend to run to you if they get on the floor.
In Peter's case, he really does not want to be on the floor. Although he's become a bossy rat with his buddies, he can still be nervous and wimpy. In this video, he's not freaking out rather he wants to be with his human and not on the unknown floor.
By the way, Walter (Walternate) of yesterday's video figured out how to get off the bed or the couch and just loves exploring the floor of the house. Sigh, now, Walternate requires constant supervision when he's out of the cage.