well yeah. Cuz the guy tries busting through the wall and ends up breaking his arm. after, the girl asks to draw with her again, but the guy replies that he can't (obviously cuz of his injured arm). So after (you don't see the girl cut her arm), the guy returns and there's a gift box in front of him, the girl tells him to open. There was an suprised expression on his face, and I think they only showed for a split second an arm in the box. Also the girl was wearing this robe thing, which she didn't wear before. And after they showed the arm, on the glass it said, "Want to draw with me", which is self explanatory in itself.
Okay in all fairness, even if she cuts her arm off doesnt mean he can draw with it.... like wtf, kind of stupid, you think about it. i do get the love element all that titanic sht ( drama ) but yeahh still wtf?