Corrected entry: When Michael is about to reveal E.T. to Mary ("Remember the goblin?"), the camera dollies back through the hallway, past a large potted plant. The plant is moving because the camera (or the crewmember operating the camera) brushed against it.
JC Fernandez
13th Aug 2007
Correction: There are several better explanations for the slight movement of the plant including the characters brushing past it or a breeze.