By the way, Johnson has a very clear out from all this, but he won't do it due to his selfishness.
The way out is a second referendum, now a clear choice between remain and no deal.
May, when her deal failed the second time in the Commons, should have called a referendum on her deal vs. remain at that time.
Neither of them do it because they are bound by stupid self-imposed red lines and about 'respecting the will of the people'... in a vague, non-binary vote, so vague in fact that it's the reason for this whole mess now.
If Johnson called the referendum now, with his GE being blocked, he could frame it as trusting the people to support him, give an unambiguous vote of intent as to what they want. Win or lose, the issue is settled and he'd go down as, at the very least, a 'decisive' Prime Minister who brought the beginning of the end of all this.
But he won't, because he - probably rightly - believes his better chance of success is a GE because of the unpopularity of no deal. He sees it as the chance to let him continue to be PM, despite the fact in all likelihood we'd still have a similar parliamentary split between leave and remain after a GE, so it'd resolve absolutely nothing.
So, as per usual, Johnson isn't acting in the public interest. It's all about him.