Gus Grissom didn’t sink the Liberty Bell 7 Mercury capsule
http://www.space.com/missionlaunches/missions/liberty_bell_000617.html
“Following the splashdown of “Liberty Bell 7”, the hatch, which had explosive bolts, blew off prematurely, letting water into the capsule and into Grissom’s suit. Grissom nearly drowned but was rescued by helicopter, while the spacecraft sank in deep water. Grissom maintained he did nothing to set off the explosives to blow the hatch, and NASA officials agreed. The craft was recovered in 1999 but there was no evidence of how the hatch had been opened. However, later experience showed that the force necessary to trigger the initiator for the explosive egress system would leave a major bruise, and Grissom had no such injury. Guenter Wendt, “Pad Fuhrer” for most of the early American space launches, believes that the cover protecting the external release actuator was accidentally lost, then the T-handle may have been pulled by a parachute shroud line, or have been damaged by the heat of re-entry and fired when it contracted during cooling.”
http://en.wikipedia.org/wiki/Gus_Grissom