Is this what its like Journeying inside the Tesseract.

Portal has a few fundamental rules, and this is the big one: when you go in one portal, you come out the other. Doesn’t matter how far apart they are. But what happens when you smoosh two portals together like physics-defying bread and stick yourself in the middle like foolhardy lunch meat? The answer, as demonstrated in this experiment by YouTuber CrowbCat, is everything.
I don’t know what to say, other than… My God, it’s full of spaaaaaaaaace!
Source: gamesradar.com

This is what happens when you’re crushed between two Portals