I had another one.
I was flying a modified Elysium transport that handled like a fighter. It could fire Kaysers forward, and had 3 missile bays, one of which fired Helios torpedoes. It had an afterburner with a max speed of only 90, though.
I was supposed to destroy these two groups of stations/ships (I forget what they were exactly but I remember at least one Faustus at each one), I was doing hit-and-run attacks, and I fired a pair of Helios warheads then turned away and used my afterburner to escape the blast radius.
Once the two groups were destroyed, a huge Shivan fleet jumped in, with literally thousands of Sathanas juggernauts and many other types of ships.
I got a signal from command saying that they were going to activate an experimental new type of engine on my ship, which was faster than a normal drive but slower than a jump drive. Then I saw my ship flying backwards at crazy speeds, causing the entire battlefield to zoom out quickly (I could see the thousands of Shivan ships, many of them were battling GTVA ships, including at least one Colossus, although the GTVA was severely outnumbered). I'd estimate that my ship was traveling at least many thousands of m/s.
At this point, I was somehow made aware that, in the story of the mission/campaign I was playing, this massive Shivan fleet was just a bluff, and most of the ships were illusions of some sort. But in-game, they were actual ships. So I decided to activate the cheat codes and try to kill all of them with the kill code. In reality this would have been pretty much futile, as it takes 10 kill codes to destroy one Sathanas, and doing that to thousands of them would take hours, even if I held down the button and auto-acquired new targets. But in the dream it worked, and soon the entire fleet was exploding (there were also some other ships exploding that were even bigger than the Sathanas class, but they didn't look Shivan or GTVA).
I then received an order to dock with and enter this huge space station (it looked to have been carved out of an asteroid, with dimensions of maybe 30 x 50 km. There were actually several of these stations scattered around, but I was supposed to dock with one specific one). I realized that if I had played the mission normally, this would be easy as the station would stay still, but since I used cheats to destroy the entire Shivan fleet, the explosions were pushing the station and causing it to rotate a bit, so lining up with and getting inside the docking bay was kind of difficult, but I did it.
The inside of the station was fully navigable, with many complex rooms and chambers, other ships docked inside, etc. The station was still drifting from the force of the explosions so I had to be careful not to bump into the walls. I received an order to go to the 'upper level' of the station to dock my ship and end the mission, but the place was so large and complex that I couldn't find where I was supposed to go (even with a Descent - style 3D map to help).
I accidentally went down a corridor that led to a door I passed through, that wound up at a dead end. The door was one way, so I couldn't go back. But in the dead end room there was a computer that I could use to access the internet (yes, in the game... it was a weird dream after all) and I looked up the cheat code that could make you noclip (because I had forgotten it). In the dream, the cheat was the word "sweater". I used it and went back through the one-way door, and eventually found where I was supposed to go.