
Originally Posted by
Aralith
You're missing one key point. The reason that Cloud had Geostigma in the first place was because the Jenova cells in is body had become inactive. This is not stated in the movie, but a logical deduction since he had no other chance to come in contact with Jenova cells and neither Jenova nor Sephiroth had been utilizing Cloud's unique abilities for two years (i.e. being able to control him). So it would be fair to say, that since Geostigma is a fatal, crippling disease, the lack of the inactive Jenova cells causing it would make him stronger. Plus a bit of adrenaline and some serious determination.