Guld and Myung did it later on, if he actually raped her i doubt she'd even want to be in the visable area as him let alone let him touch her, she was too easily swayed, being upset maybe helped them get it on, but i truly believe he didn't go as far as rape, sure he tried to kill her, ripped her clothes while doing so, just not as far as rape. Isamu is just too cool headed for him to just let him get away with what he did (relating to possible rape). He'd have more hate wouldn't one think?
Take his mini missile fury at Isamu in the last dogfight between them, he was really pissed and let loose just the same when he caught Isamu and Myung together (what were they doing? just hugging and talking?), brought him straight back to the place where he comes back to reality with him seeing himself in the mirror.
No rapeage, champs.
He didn't have to redeem himself any further than his kamikazi with the X-9. Prefer him to have lived though. :-(