I don't see "arbitrary (relativistic?) velocities" as you say. There must be mechanical limits to the speed of the rotation here. What is unlimited is the duration that the engine spins.
When you say "weaponization of this technology could potentially threaten all life on earth", I actually think of nuclear energy, as in the one we have right now.
> When you say "weaponization of this technology could potentially threaten all life on earth", I actually think of nuclear energy, as in the one we have right now.
The difference is that nuclear engineering is expensive and difficult. Magnets are cheap and ubiquitous. A nuclear reaction can continue only so long as there's fuel. Infinite free energy is, well... Infinite.
Somehow, I don't think you're taking this seriously. If you really believe in the potential of this technology, it should scare the daylights out of you.