In the novel he doesn't just lose an arm, he's hurt way worse, part of his body gone. And he doesn't say he'll try to get hurt as little as possible but the very opposite: as MUCH as possible, because he wants to make himself as harmless as he can for Yohan so he can't hurt him if he completely loses himself. He was trying to give Yohan a way to escape because he feared what he could do to him while in his most violent insane estate (from fighting the pseudosubway) (/TДT)/
In the novel he doesn't just lose an arm, he's hurt way worse, part of his body gone. And he doesn't say he'll try to get hurt as little as possible but the very opposite: as MUCH as possible, because he wants to make himself as harmless as he can for Yohan so he can't hurt him if he completely loses himself. He was trying to give Yohan a way to escape because he feared what he could do to him while in his most violent insane estate (from fighting the pseudosubway) (/TДT)/