The investigation eventually separates the prosthetic arm events into two categories: serious (in which Kristen Shaw's strangulation and a twenty-car pile-up appear together) and juvenile pranks (which comprises all other events). One of those "juvenile pranks" is the chopping off of a chef's fingers. This is not considered "serious?"
One of the "Arm-ageddon" events is the destruction of artwork, where a prosthetic arm, in defiance of the laws of physics, pulls a tour guide forward. The hacking of a robotic arm's movement does not adequately explain the force required to pull a human body through space.