I agree, Manaus is a grand place for a layover, though I don't know if I would worry about being put behind pipes in Brazil for having #2 disintegrate on me. Maybe the Mechanic might, but not the flight crew. You can't even pre-flight that one without a cherry picker, you just gotta cross your fingers and hope the MX department did their job with conscience. Also, their "payload" might have just consisted of empty pallets. I know that was always a technicality, since if the airline doesn't own the pallets, then technically they are "Payload". Even if it was real payload, then hopefully the competent load master made for an aft CG. That means with less aft weight after shedding most of #2, the plane would have a more forward CG so being out of trim range would be the least of my worries.
And I also agree with the previous post, Medellin is a lot more work to land and take off out of than Bogota, and I can say that with certainty because I have loads of experience flying in and out of Manaus, Bogota, Medellin in DC-10 freighters working for a similar "Miami operation". And there are not a lot of emergency landing fields between Manaus and Bogota (like none), and Medellin is even further away than Bogota. It's not like taking off from New York and heading onwards to Houston or something like that on two.
I personally had #2 die on me (lost oil pressure, not catastrophic) somewhere north of Ouagadougou (yes Ouagadougou, those who know the area understand why I didn't decide to land anywhere there). Because yes, on a 3 holer, depending on the circumstances, it may indeed be better to continue. I decided to venture onward on 2 engines toward "civilization". But it was daylight, and severe clear all the way so my decision was easy. Though because of single engine drift down thoughts and wx/fuel, I decided on diverting to MXP rather than going on to BRU straight over Mt Blanc. Some have said that the ENAC (Italian CAA) also shoot first and ask questions later, but fortunately I never heard a word.
No one mentioned the wx conditions at Manaus for a return after dump, so I don't know all the facts. All I know is I would be a bit puckered flying over impassable swamp and some of the highest terrain in the hemisphere all with liberal CB's topping 50,000 feet, and with no en route alternates to speak of, with that much damage. I am sure those jockeys needed a cold beer and a good shot of aguardiente after they settled down. Glad they made it, and the rest, the experts will sort out.