Karkat has quite a bit of experience with dream bubbles by now. It doesn't take him long at all to figure out what's going on. The harder part is vacating his memory as soon as he can so that no one else will find it. The Land of Pulse and Haze isn't the easiest place to navigate and...maybe...he's feeling a little nostalgic.

Maybe.

Just a little.

So he lingers a little more than he really ought to, making it possible for others to chance upon it.