This might work with good friends who are young and have a huge amount of time on their hands. I could have lived with this in high school.
As an adult with a very limited time allotted for gaming, I would be supremely pissed off if a DM pulled this stunt. I would at the very least never be a player in a game where they were DMing, and I would further hold it out as a cautionary tale for future DMs... ("you'd never believe what this one bozo we had did." It would certainly be submitted to the many threads about the "worst DM ever".) At the worst, I might never play with that person again in any capacity.
Basically, this is like very long exposition, only longer. No matter what the players do, you have your own agenda and you are going to be railroading them.
Imagine how the players feel 1.5 hours into the session when they realize that NOTHING they did was going to have any impact. Basically, they were bystanders while you as the GM did all of the playing. They were not playing, because nothing they did was going to matter.
The social dynamic I expect is that the GM gets to play lots of roles, they get to be the center of attention, they are trusted to pick out interesting elements that will make for good gaming sessions. They might pick parts of published adventures or use them wholesale. They might pick up bits from movies they've seen. whatever... the GM has a lot of freedom.
The players get to decide how they will react to the situation. They guide the narrative through their choices. The players make the story through their actions or inaction.
In this case, you are taking away the players agency by putting them in a no-win situation. No matter what happens, it will have been a waste of time because the outcome was planned in advance.
VERY BAD IDEA.
Better idea: just say this: "Your characters have horrible nightmares, imagining their death at the hands of a particular BBEG". It accomplishes the exact same thing as your original plan, except that it only takes 10 seconds and doesn't waste half your players evening. I can forgive a lot of things from friends, but I will not tolerate their intentionally wasting my time.