Hmmmmm (part three)

New Scenario:
The edges that define the "portal" between the never-ending space and the space we live in are extremely nebulous.

You would just sort of pass through, although the time it takes to pass would be so brief that you would not notice, to this alternate dimension. What you step into is determined by the time period at which you enter the new dimension. If enough time has been allowed, you may not even notice the difference. This however allows for some ambiguity as well, since human senses are not accurate enough to notice many instant changes in their lives. Did you take an exact note of the location of your toothbrush this morning, to the extent that you would notice if it were moved a quarter-inch to the left? This may seem insignificant, but that's exactly the point. You don't notice the ensuing course of events, and the difference between those events and the events that would have transpired if your toothbrush had not been touched by any forces at all. But that's impossible, considering that the random forces of pressure may have moved it somehow, in any direction for any length however immeasurable. But you may never know the difference.