B9 then read the message again and turned the AC power switch off and back on.After failing to confirm all arm carts had been detected (refer to step 1.20 for associated findings), B11 and C11 were confused when some but not all arms carts had power.C11 instructed B11 to press the illuminated button on the front of one of the arm carts, and B11 subsequently pressed the system pause button.