But what doesn't make sense is that the pilots (both captains I understand) were based at Congonhas and very experienced on type and at the airport. They would have surely landed there hundreds of times in the past, thereby knowing the exact performance of the aircraft in relation to the runway.
My guess is that they hydroplaned sometime after the initial touchdown and tried to GA out of it. The reason for this is that they knew that they wouldn't stop in time and thereofore head over the cliff edge. Hence my previous comment about an EMAS.