Prorogation: "Rory has already said they'll meet up across the road"
They'd have to take the mace with them for that to work - although Bercow would probably help by bringing that himself.
The Queen would try to stay out of it, but I'm not sure if she has the power to refuse a PM who is determined to have his prorogation.
Hopefully, she would delay, saying she needed legal & constitutional clarification
It would be a constitutional nightmare and unclear who was in charge, but better than just accepting prorogation
To stop No Deal, the (moved) HoC would still have to vote NC and bring down the govt,
but in those circumstances, there should be enough MPs who'd vote for that.