Dead man's switch. Or, crushing the car mixed gasoline with oil with the heat of the engine and possible electrical shorts etc. Mix all of those factors with explosives and BOOM!
But overall it is a very poorly executed attack. In fact, it makes no sense at all. The car races up to confront the tank I guess. Then stops. The three shooters to not exit the vehicle. If I saw a tank rolling toward me, I would get the HELL out of the car. I wouldn't sit there and wait for the tank.
Also, if you look at the white car and truck on the right, they simply rolled on by the checkpoint. Why wouldn't the bomber, after seeing the tank, veer to the right and go deeper in, if that is what they wanted? I don't understand the whole scenario. Including why the tank thought it would be a good idea to roll on top of a car loaded with explosives. Then the tank turns around and carefully inches around the car to avoid running over it a second time. Why?
It is a weird video. Even the explosion itself is weird. It tends to go more upward than outward, and there more actual fire in it than I would expect to see. I don't know. It's a mystery to me?
