MacGyver's homemade forge is a very popular DIY project. However since he used plaster of Paris to fill the bucket he would have to wait days for it to dry in order to use it. Otherwise the water still suspended in the plaster would boil off and the forge would explode.
After cutting a hole in the floor of the vehicle, an expansion bar could have been placed between the brake pedal and the seat allowing Bozer to remove his foot from the pedal. This would have also given them more time to figure out what could be done with the bomb.