It's a bit complicated. It does save over 30 seconds so you could even fail it once or twice and still just about save time. With some practice I think you can do it with 100% consistency. The real problem is how much money you lose. Doing that and still affording the minigun at the start of level 8 is gonna require that you pick up a lot more money earlier and/or get really good RNG. In the current WR even without doing fast 7 I don't have enough money to buy the minigun instantly which loses almost as much time as doing it saves. Other option is buying the minigun later, which then means you have to do the rest of level 8 without it which is really risky because there's a few places where because of the respawn layout you might lose all the time you saved from dying once. If the run is optimised a bit more fast 7 will for sure be used though it saves too much time to be ignored.
I did play them thinking I might, but they just don't seem as much fun to run. Enemies take more hits to kill, the level design really restricts your movement, there doesn't seem to be as much room for development, and the games are just longer. None of this means they're worse games, just that they're not to my taste when it comes to speedrunning specifically.
