The Death of Ensign Harper

M-5 detects the Woden, an unmanned freighter that is not part of the test, and attacks with real weapons, destroying it. Captain Kirk orders M-5 taken offline, but Dr. Daystrom continues to believe it is working correctly, and refuses. Kirk tries to disconnect M-5, but discovers it is protecting itself with a force field. Chief Engineer Scott assigns Ensign Harper, a technician, to unplug the main connection, but the crewman is killed in the process.