These are actual doors created by magical means between parallel dimensions.

I use the computer only to travel between dimensions.

The Looters could indeed travel between dimensions, and in fact had been doing so for nearly a century.

Maybe this machine is moving people between parallel dimensions where things are just a little different.

The true test would come when the portal between dimensions opened.

The actual transition time between dimensions is only a minute or two, right?

Ah, but whatever they were, they could not follow me between dimensions!

Surely we could be a bridge between dimensions as well.

Besides, they also look for doors between dimensions through which some beings from different worlds are able to pass.

"Nothing save the space between dimensions, which, under certain conditions, can be filled."