Partial suspension hanging while kneeling

[Vegetto]

I've tested this method quite a bit now, and I've gotten to the point where I can cut off my carotid arteries by sticking my neck out while I'm kneeling facing away from the door - I've felt my body going numb and vision and hearing fading. I'm going to be using a very sturdy door in an empty office space overnight so the chances of being caught and the apparatus failing are virtually zero. My main concern is this - in this position, is there a great risk of movement into a different position that would cause the noose to loosen? And is there any way this can be avoided? I've tried doing the same thing sitting down or bending my legs but it's just not as effective, plus much less comfortable, those ways.