If it happens then ipso facto it is within the framework of reality. Anything that occurs is by definition possible because possible just means that something can occur. This overrides and supercedes any and all contrary previously existig theories about the specifics of the rules.
It may suggest a deeper set of rules for which the previously assumed rules are merely a subset or special case of.
In the matrix example everything that the rebels do in the matrix possible within the framework of the larger setting of zion and the machine city etc (and furthermore everything they do in zion and the machine city (etc) is possible in their world even though much of it is not possible in the real world due to the world of The Matrix apparently having radically different rules of human biology, electrodynamics, thermodynamics, and computer science. [though the part about human biology may not count as that's not really an intrinsic specialization, it's a subset of biology, and then chemistry and ultimately physics, so the main characters uniformly having a biological/neurological defect or maladaptation that causes death in the matrix to kill them in the zion/machine city world doesn't necessarily violate the rules even of our reality unless we know the specifics]) (edit: and Neo's woo abilities like esp and electromagnetokinesis that do violate the rules of our reality can be explained by differences in their world's physics)