If you are working inside a machine or cabinet, then yes, you'd power it down. Doing routine programming and maintenance in a robotic cell is different though. The robots typically have to be powered up in order to teach or operate them. So when you enter a live cell, you have a lockout mechanism on the safety gate. A properly locked out cell will not let the robots or other equipment in the cell operate in automatic mode, but they are still able to function manually when you allow them to. In this case, either she screwed up and failed to lock out, or someone else screwed up and let a robot in a different zone enter her locked out zone without a safety check.