Karsten does have listed 1k and 1500 times on his WA page (both from his multi-event days as a Jr I'm assuming). So he ran 2:45 and 4:44 respectively at the end of his multis when he was a kid but now that he's a man and doesn't have to bother will all those other events, could he drop a competitive 800? I'd guess no because he's definitely more of a sprinter and even the last flat 400 I saw him run didn't look impressive but it would be a very cool race to watch the buildup to and speculate about.