Mika pauses to glance at Armin at that. What he's describing reminds him of the horsemen, but those monsters just kill humans, rather than eating them.

Not that Mika sees how it's any of his business to care, anyway.

"If you'd rather go at your own pace than try to keep up with me, that's fine."

Or in other words, Mika's not going to be particularly bothered by splitting up. But neither does he see any good reason why he should stick around and wait for Armin to rest or figure out how to control his running.