When the bomb squad removes the doors from the Mercedes, no wiring is disconnected at all.
At the end of the movie liam neeson comes out of the water his hair was wet but his clothes were dry.
In the final scene where the Vehicle roles on it's side, this would cause the pressure sensor in the seat to not detect the driver as his weight now only applies perpendicular to the seat sensor. thus the bomb should have triggered the moment the vehicle rolls over as the bomb is triggered by the pressure sensor.