Do you start timing when you select 10 Year Championship or when you start the first race? Also, stop time when you cross the last finish line I assume?

Wasted 20 seconds missing the first seam jump into Keyes skip. Not an optimal route, but uploaded as a baseline for improvement and timing purposes. Looking at the floor while strafing, headed toward the second elevator drop, seems to keep enemies from targeting you and avoiding any added slowdown.

Fitter's Octopus route with solid, early use of the Venom. Make the most of the Magrail, then replace with a HS-90. When clearing rooms, make sure to keep an eye on your main weapon's ammo count. Reload in between white air lock rooms.

Pick up an Assault Rifle for the second half of the mission. Should be able to keep your ammo constantly refreshed until you reach the spiral ascending reactor, where you can replace with dual wield HS-90s. In the last room, spam any remaining grenades as you exit the air lock.

My setup for skipping the zip lining shenanigans in Crab Key.