If Government can't function -- and, by extension, if Parliament can't either -- then the only other alternative is to return the decision to the people. I don't yet see a second referendum being "imminent", but the odds must be shortening significantly.
Let's not get stuck over remainer wishful thinking.
It'd take a politician with no respect for the democratic decision made earlier, elected as the new leader of the Tories before there was any suggestion of such a betrayal of government responsibility on delivering the decision. Even then it'd need to get past the cabinet, then the House.