Re, the Clutch interlock.

In the US cars with a manual transmission are required to have a clutch interlock that won't let the car start unless the clutch is pressed in. Most 4x4s have a switch that when pressed will allow you to turn over the starter with the clutch engaged. This is primarly used when you are in 1st gear, 4L and halfway up a rock or other obstical that you don't want to roll back on. If you stall the engine you simply hit the button and crank the motor over. By using this method you don't lose any ground (remember drivetrain slack is increased when you are in 4L) and the starter has enough torque to turn the motor over because when you are in 4l it takes less torque to turn the wheels.