I got stuck on a slightly raised piece of ground roughly in the centre of the map (it looked like a separate mesh rather than part of the geometry of the terrain). Presumably the technical issue was that the car was elevated in such a way that none of the wheels were able to gain enough traction for the car to start moving again 🤔
(Now that I think about it, I didn't try melee - that's a pretty mighty foot Caleb's got right there...! If melee doesn't already work on the car yet, that could be a thematically consistent solution... 😁)