"It's the same City," Karkat confirms. "Different universe, though."

In part, the lack of his own empathy helps Karkat distance himself from their surroundings, remind him they aren't the same, no matter how identical they may look. There's less of a connection, this way. Being limited to merely his own emotions feels more isolated than it should, and that sense of isolation deepens here, in these familiar surroundings, surroundings he'd never experienced without that power.

It's unthinking, almost automatic, when he turns, and begins to walk. Home is further away, would require a cab or a bus to reach, but there is somewhere else he wants to see, somewhere much, much closer. Queasy anticipation is right.