Idea for "Forbidden Planet" sequel

Here's an idea for a sequel to Forbidden Planet. Yeah, I know J. Michael Straczynski is working on one. But here it is anyway.

Forbidden Planet was a groundbreaking SF movie from 1956. "Groundbreaking" as-in Star Trek stole most of its basic concepts from it. The ideas behind it were intelligent. The writing was literate. It holds up amazingly well today.

OK, the plot of the original. Skip this if you know it.

Basically, a ship from earth tries to rescue Dr. Morbius and his daughter from Altair IV. Dr. Morbius is living on the planet of the Krell, a dead race. Something wiped them out a million years ago. They left behind a vast underground computer connected to a bank of nuclear reactors that exists to do ... something.

Morbius and his daughter are the only survivors of colonists of the Bellerophon. Awhile back, Dr. M. used some of the left-over Krell tech to expand his IQ. He also built a robot named Robby. When the rescue expedition attempts to get Dr. M. and his daughter to leave, an energy monster starts killing them. It turns out, the monster is a projection of Dr. M's subconscious -- a "monster from the Id." We discover that the underground computer exists to project energy: it turns whatever you imagine into reality. That's not such a good thing, as the Krell sadly discovered. The Krell were so advanced, they didn't realize their Id would create monsters, and so they died. Dr. M., for reasons of incestuous jealousy, is also creating a monster. He sacrifices himself. The planet blows up. The dude we would come to know and love in "Police Story" zips away with his daughter in a flying saucer. End.

OK, brilliant. But there's a basic flaw.

There's a scene where Dr. Morbius commands Robby the robot to destroy the energy monster. Robby won't, because he realizes the monster is a projection of Dr. Morbius. He can't kill a human being; he's operating on some version of Asimov's Three Laws of Robotics. Robby is, basically, Krell technology.

It implies that the Krell matter-generating machine would work along the same lines. It would be incapable of killing.

It's also logical to assume that the Krell, being ridiculously evolved, would be smart enough to remember their primitive beginnings. If they created a matter-generating machine, they'd put in fail-safe devices to block murderous impulses. What follows from that ...

Somebody deliberately deactivated the great machine's fail safe devices. The Krell weren't idiot angels who forgot they once were devils. That's not the explanation. They were deliberately betrayed.

And, one day ...

An alien race appears on earth one day with a promise.

Anything you imagine can become reality.

There's a machine that can do that.

We can build it for you.

The project gets the green light.

Earth starts building a great machine of its own.

Off in deep space, the United Planets Cruiser C-57D is dealing with the Altair IV situation. They don't know what's happening on earth yet -- but they will. If the great machine is built, we'll all be dead.

The clock is ticking.