From Halopedia, the Halo wiki
Commander Yance was an officer in the UNSC Navy and the commanding officer aboard the UNSC Nereid, a mixed cargo hauler. In October of 2558, the ship was carrying a platoon of marines and a group of construction workers and their equipment as part of a simple mission. On the 28th of October, however, Cortana launched her plan to take over the galaxy with the assistance of the Created. While the Nereid was traveling through slipstream space there was a sudden burst of light and a powerful pulse of energy that caused the vessel to not only drop out of slipspace but also to lose all power. Yance was off-shift at the time and was taking a shower in his private quarters when the attack came. Though power immediately was cut all throughout the ship, the water jets continued to release what had already built up inside them. With the water unable to drain in a zero-gee environment, and with the doors to the shower electronically sealed, Yance drowned. His body was discovered soon afterward by Lieutenant Commander Elaine Coffey, Major Kell Tanris, and Sergeant Chan.
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