Rocket science it is not - this also happened in Seattle a month or so ago when a Nat'l Guard type asked if the metal detector should be plugged in. This is so basic it is inconceivable that it can get screwed up. Basic SOP should say check at the start of each shift to make the @#%&@ machine is plugged in, periodically check it again, look for the power on light - DUH!
Once again the feds have missed the boat, we don't need barely functional live bodies at checkpoints - we need law enforcement types who are accountable.
If LAX was my airport I would fire every one from the manager of the security types down to the slug who couldn't keep the machine plugged in
Even better - hard wire the suckers