The question arises especially in the case of the cat in a box (Fig. 1) and in all quantum mechanics in general: is the observer's clock inside or outside the box?

The most important part of the Schrödinger cat in a box paradox is intentionally missing: is the observer's clock inside or outside the box?

In Einstein's special relativity, there are two clocks, one in each frame (Fig. 2), which is a big step forward.

However, Einstein did not explicitly define the time step. In contrast, in the 4D x-t space of the Transition-B matrix, the observer's clock is inside the experimental box, which is implied by the universal laws of nature.