modifying where Samus is placed in the next room.
Exiting G-mode will teleport Samus to position where she touched the Samus Eater.
At the start of the door transition, Samus' X and Y pixel positions are reduced modulo 256 (the size of a screen),
so the relative position within the screen is all the matters (not the absolute position in the room).
The transition must be touched 2 frames after control is regained after releasing X-Ray.
A normalized method to do this is to position Samus slightly more than 1 pixel from the door (but less than $1.3 pixels away),
then hold forward toward the door while X-Ray is released.
Correct subpixels for this method can be obtained in the following way: 1) jump and press against a wall above,
2) jump and do a mid-air turnaround (making sure not to be in front of a wall when turning), which moves Samus back by half a pixel,
3) moonwalking back toward the door until 2 pixels away;
4) jump and do a turnaround mid-air toward the door.
Moonwalking moves back Samus in half-pixel increments, so in the absence of frame-perfect timing there is a 50% chance of ending in the correct position.
If Samus is 2 pixels away from the door after the final jump turnaround, then the position is correct;
if Samus is 1 pixel away from the door, then the position is incorrect, and the setup should be repeated.
See also: Tech Page