I know real movie dollies can roll on a smooth surface, but look at the camera movement at 3:51 - that's not a dolly. I agree with wgzn, this was shot from a steerable vehicle with the operator sitting backwards as he shot.
I have a wheelchair with a back that folds flat. One person can run pushing it while the carmera operator lays on their belly and shoots around them backwards.
BTW - cost was $28 at a thrift store.
