"Makes sense to me," Lyle said, because it was easier than I'll do it.

Reep likely wasn't even going to be in the Arenas, and having to kill someone -- even someone who would be a clear and present threat to all life in all realities -- well, it would probably break Brainy. It probably wouldn't break Rokk, but Lyle didn't want to see him have to make that choice and deal with the psychological fall-out. Not if he could take that burden instead.

Besides, they'd start arguing with him if he flat-out volunteered; and that might draw more attention to their little complete failure to kill anyone else than they wanted.