Corrected entry: When the pinch is activated and all the power is cut off in Las Vegas, how does George Clooney and Matt Damon use their pulley system to go down the elevator if the pulley system is also equipped with electronics, because you can obviously see the red lights turn on when the pulley is attached to the wall (electromagnets, presumably). So the pulley system shouldn't work, just like all the electronic equipment.
Corrected entry: When George Clooney and Matt Damon are going down the elevator shaft, the laserbeams are turned off for a short amount of time. Both of their ropes are short and they have to cut them. Right when they drop from the ropes the laserbeams are turned back on. Wouldn't the ropes left dangling set off the alarms?