Backing into corners and drifting out ... in the wet! That's one very skilled rider: makes me feel like a rank novice in the rain. Of course doing that on the street would be way past the wrong side of crazy. I loved the Whooo! and AYIIII! and Italian for Yikes! from the commentators.
If it has already been done, it is safe to assume it is possible to do it.
On the other hand, if it has not been done never assume it is impossible to do it.
------- Rob --------