Bumping this for the upcoming league.
Important notes I learned when revisiting the strat:
-Because one of the two guards warps the mainframe, he'll arrive there before the other. When guards reach their destination and stop hunting you down, they stand in place for a moment, and then spin/step around. Because of this, the distance from the mainframe on the glass where you perform the lure is important. If you're far to the right or at the middle of the glass, it's not enough time for the other guard to open the door, so always perform your lure to the left.
-You must stare at the pink wall for about 5 seconds to unload the mainframe long enough to let it open. Additional quickpauses do nothing, lookdown does nothing, and other rituals do nothing. Just face the wall long enough.
-My leave timing was 5 quickpause and a bit on a fast guard hurt animation, and 6-7 quickpauses and a bit on slower reactions. Aim for the chest to avoid losing time, and make sure you don't leave too early and fail the lure or leave too late and lose time unnecessarily.
While my run's speed isn't the fastest, it's a clean, perfect example of how to perform the mainframe lure.
1) Go to left of glass.
2/3) Shoot the mainframe guard in the chest for fastest reactions / shoot a stray bullet or more to lure the other guard.
4) Perform the correct number of quickpauses based on the guard reaction for the correct waiting time, and to allow for the fastest pauses possible.
5) Stare at the pink wall and pause. If you intend to kill the guards instead of inserting the disk immediately, I suggest still pausing and switching to AR33 as a means of timing.
6) Wait an extra 1-2 seconds while charging full speed, then turn and prepare for the glass opening. Make sure to wait a moment after the sound so you don't get stuck on the door opening.
Do not quickpause here as it does nothing and you lose full speed.7) Don't get rekt.
If you follow these steps, you will get glass opening approximately 90% of your runs.
Troubleshooting:
1) If you see a guard come around the corner while waiting for the glass opening, you left too early and the 10-second guard tracking timer didn't reach 10 seconds.
2) If only one guard goes to the glass and the other isn't around the corner, your lure shot missed. Use the marking on the mainframe as a visual cue.
3) If both guards are at the glass and you performed everything correctly, you simply got unlucky. Try again.
One more tip: If you use the Grenade strategy for blowing up the exhaust bay guards, you want to prime mid-way down the first hall. You can prime later if you want to be more cautious as glass guards hitting you means you'll throw the nade prematurely. I also suggest checking your Grenade count in the pause menu before the glass to see how many you have. 1 is ideal because after you throw it, you'll automatically switch to AR33. If you have 2-3, you need to backswitch. If you have 0, I suggest going for a console boost.
Now let's see even more runs with this strategy!