Per the title, a dead man's switch is a fail-safe lever or peddle that is automatically operated in case the human operator becomes incapacitated commonly used in locomotives, freight elevators, lawn mowers, chainsaws and snowblowers.
Seen at about 27 minutes on the bottom of the TV monitor screen are the same symbols used in Stargate for the "chevrons".
The helicopter seen in the opening sequence is a Bell 206 JetRanger with floats attached to the landing skids.