A shoe string string theory
The leading and current theory in physics is string theory, a string which connects multiple dimensional realms. Despite that virtually all professors of physics are students of string theory, there is no good evidence to support the theory. It’s all theory and nothing but theory. So far no way is known to test it.
Stepping or flying through a doorway, one moment in one dimension and in the next moment arriving in another dimension, but that moment seemed a lifetime when you were in it. That’s string theory.
Your task, if you choose to accept it, is to figure out why you took that step.