After solving this puzzle myself, this puzzle seems like it probably has several solutions. Also, why does that Pink All Door start with 12 copies if you can make as many copies of it as you want anyways?
It's meant as an enforcement mechanism so you cannot reuse the same set of Pink Keys to alter the red count in between trips to the left. It has 12 copies so that you absolutely cannot bypass it.
But you CAN bypass it; just use a Negative Master Key while walking over it, and the animation protects you. There probably should have been a Blank Pure Lock on that door if it's an enforcement mechanism.