This game runs in 60fps, meaning the fastest possible speedrun is looking down and interacting with the mat in a single frame. This would give the time of 0.016s (1 / 60 = ~0.016). So far, I have been unable to get this time. My speedrun is done in 2 frames. (1 / 60 * 2 = ~0.033). This time still requires pretty much frame perfect inputs and took me many, many attempts to achieve.
As for the mat thing, the reason this happens is that upon moving the mouse, it changes the variable that stores the camera angle, but the camera doesn't react until the next frame. This means that if my speedrun skipped the first frame, then I completed the 2 inputs in the second frame (as I said above), the camera would not have had time to react to the movement before the game ended.
I'm not that great at explaining things but I hope this clears some things up for you.