Dude was transporting fireworks in the car. They caught on fire. For whatever reason. Doors locked automatically. As designed. The guy couldn't find the hidden release lever. And so he burned to death.
He was also transporting cans of natural gas and other fuels. Who loads their truck to the brim with fireworks and anything that is highly explosive and then "accidentally" detonates it at the entrance of a hotel?
It's a bit of a weird terrorist attack though. The whole thing about car bombs is that It's supposed to be a portable bomb. The idea is you get out before setting it off.
Also what's the point of blowing up the outside of one of his businesses, it wasn't like he was in there.
So it doesn't immediately feel like a terrorist attack.
Oh, the steel on that thing is just fiine! Give it a decent polish, slap some more poorly thought out tech in it, and you can roll out another death trap within a couple of weeks!