Video camera from hallway shows the chair being bumped and no one is there.
As the investigator is sitting, the chair gets bumped from behind and no one is there behind the chair
Orb is coming from the right side of the room and passes through the investigator.
Watching carefully, you can see the exercise ball move when the investigators are currently in the same room without any knowledge of it being moved. (all heating/air vents have been disabled)
Motion sensor goes off and no one is in the room.