Eridan winces, 60% mortification and 40% at just the sheer fuckin' volume of Karkat's voice. It's been just long enough that he'd almost forgotten how goddamn shrill this unbearable motherfucker is! But not nearly long enough for him to forget the last time he actually saw Karkat. It was... well, right about when he got brutally bisected by the fashion hag.

(For reasons that are! Absolutely! Not relevant here!)

He immediately regains (some) of his composure, throwing a hand up to lean against the wall as if he expected to be caught out. He did not. He didn't even expect to be noticed, to be honest!

What does a guy say when confronted by (the doomed copy of) a close personal friend who you closely and personally ruined the life of?

"H-Hey."

Nailed it.