Extraction is easy. It's the replacement relationship that requires further thought. And no one was going to hold talks on that until it was proven we had the sense to get out.
Danny had the right answer, although if some parts of the UK is determined to destroy the Union (using Brexit as the feeble excuse) then there's nothing to stop them pushing for it.
IMO clearly the main concern is that we get sovereignty back, the Union is very important but not so important that we let those who need a European master dictating to them, to drag us back. If Scotland's leaders thinks it is better off as a very small part of the EU morass, then they are at liberty to ask the public yet again whether they want to split from the UK. And if the public are fed up with being asked they will know what to do at the next election.
Meanwhile there should be no control handed over to Sturgeon to dictate pace, nor destruction of the exit, nor whether anything happens at all.