And in the Grauniad’s comments we find a solution.

[johnny9fingers]

I found this about the most likely route to avoid Boris and Dominic doing a “find the lady” on the rest of us.

Apparently it’s all fairly mechanistic, deterministic and clockwork:

MPs pass the Law blocking No Deal Brexit
Vote of No Confidence immediately called
Johnson demands General Election under Fixed Term Parliaments Act
Vote of No Confidence Passes
Vote for GE rejected, fails to get required two thirds of MPs
MPs select Caretaker PM commanding the support of majority the House
*** Prorogue Intermission ***
Johnson refuses to resign as PM
MPs send Humble Address to Queen
Queen sacks PM
Queen appoints Caretaker PM nominated by MPs
Caretaker PM moves Brexit Date out ahead of any General Election
Caretaker PM calls General Election

Thanks to LucianOfSamosata from the Graun.