This is not video game style remote driving. The car is always in control, and its primitive object avoidance routines won't let it crash into a barrier. This is presumably to allow humans to help make higher-level decisions. For example, maybe the car asks something like "this road is blocked. I could cross the double yellow line to get around, or I could reverse and go a different way. Both of these options are suboptimal, can you help me choose?"
The most extreme type of assistance could maybe be a human drawing or modifying the vehicle's planned path (if you watch any of the Waymo example videos, you'll see the immediate path that the vehicle is planning to take). But even in this scenario, the car is still responsible for navigating that path and avoiding any obstacles.