In the near future, sensory deprivation space tours become popular among the west-coast-hippie-billionaire set ("Explore inner space -- from outer space!"). Such things are relatively profitable, because occupants willingly lock themselves in tiny sound-proof unlighted rooms and lay in their sleeping bags for large portions of the trip and don't particularly care about the scenery, so cheap cargo spacecraft that typically dock at low-earth-orbit space stations (i.e., no capability for landing or atmospheres) can be repurposed as luxury cruise lines without actually adding any luxuries. Unfortunately, on one such ship, a string of violent closed-room murders occur. Because a small segment of the crew has access to an emergency unlock for the rooms, they are suspect -- however, ships logs indicate the doors never having opened, either automatically or from the inside, and security footage agrees. Eventually, it becomes clear that the culprit is a popular grey-legal hallucinogen that has a side effect of causing short bursts of increased blood pressure -- which, in people who are already stress-prone and already not particularly physically fit can cause violent arterial bursts when gravity is no longer enforcing normal patterns of blood flow; many of the customers took this immediately upon entering their sensory deprivation chambers and then their necks exploded 15-20 hours later.
