A pacemaker is a medical device designed to regulate the beating of the heart. In normal medical practices, a pacemaker is used to assist in regulating the heartbeat of a patient whose heart has lost the ability to do so on its own. While on Hydra Island, however, Ben made Sawyer believe he had been given a modified pacemaker which would stop his heart from beating if it got over a certain rate. ("Every Man for Himself")
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