To stop Ted from shocking Alex Larson with a defibrillator, Darby pulls the plug from the AC outlet. All standard defibs (especially this HP CodeMaster XL/XL+ Defibrillator/Monitor) have batteries and they are only plugged in to keep the batteries charged.So pulling the plug would not render this defib inoperable. Also defibs are kept in a central location in the hallways and not in patient's rooms.