In season one, the episode called 'Songs of Praise', Geraldine sits on the sofa arm and Tristan sits on the seat. She opens the coffee jar and says 'Oh look, it's a new jar. I love that popping noise it makes, don't you?' then pops the jar. Now, when she raises her hand and comes down, the popping sound is ridicolously early, so early that the sound comes when her hand is halfway to the jar. Honestly, it's sooo obvious!