"Oh Shit" moments...

Down Shaftesbury avenue, near Chinatown, there are plenty of small traffic islands. I am cycling pretty fast southwards as it's Saturday morning and the streets are fairly empty. Still this is not fast enough for a white van behind me who needs to assert his car supremacy.

He speeds up, properly revving his engine, and overtakes me. But his front right wheel hits a traffic island with a loud bang while he is immediately next to me. I am pretty sure he just didn't see the traffic island as he accelerated. My guess is that his aggression got the better of him so that he only focused on me, not the road ahead. Because of his speed the traffic island makes the car jump rather than stop, but it only makes the left side jump so the van inevitably tips sideways while I am right next to it.
For a split second I have the white van to my immediate right leaning/dipping fast towards me reaching a roughly 70 degrees angle. For that second I was certain I was going to get crushed beneath it. But again, possibly because of its speed, it continues forward and seems able to drive whilst presumably only touching the tarmac with its two left wheels. (I couldn't see if his right wheels were on the island or in the air). Since the traffic island was relatively small it clears it after a metre or two and lands back on all four wheels after about a second more.

I am not too clued up about physics so I don't know how much more the van would have had to lean sideways before it would have keeled over and crushed me, but it was definitely the scariest moment I have had for a long time. And I just cannot see how I could have avoided it seeing as the van came fast up from behind and I was in near primary position.

Definitely an Oh Shit moment right there.

As for physics, that would depend on the load in the van, the camber on that stretch of road, speed vs elevation in the jump - Not something either you or the driver would have had time to think about right then and there.
Little else you could have done, Primary - Tick, good speed - Tick, over zealous/lack of attention van driver - Tick....... Just glad you're okay despite the epic start to your day.