There is always room for negotiation. Bilaterals is a treaty, not a diktat. And again, 2 years provides time for another referendum.
> wonder how many Swiss were aware they were voting to end their own freedom of movement, that blocking EU immigration would mean they would no longer be able to move elsewhere in the EU themselves
Everyone did. The question was how the Guillotine clauses would be executed. Which, truly, nobody knows.
The "diktat" is the thing you just voted on which says "we will not negotiate". There is always room for negotiation until you vote for a law that says "no negotiations, we are now legally mandated to do X".
> 2 years provides time for another referendum.
Voting for a no-negotiations amendment to your constitution as a negotiation tactic with the idea that you will later pass another constitutional amendment in a small window of time to revoke it is some kind of 4D checkers strategising that I suppose I am not enlightened enough to grasp.