Also, their totally was radiation damage. Elfangor mentioned human doctors have to cut out tumors. When did this come up? When the on board medical equipment was used to shrink his acquired tumor, and Loren asked what he was doing.
I have to ask what on earth you are talking about. The only occurrence of the word tumor in TAC is when Elfangor is criticizing Earth doctors, who have to surgically cut them out-mentioned in regards to Loren visiting a doctor.
More to the point, there is a big difference between kill and function. You can live a few minutes without air, but most things will pass out well before actually dying. Same with cold. Helmet may have held off oxygen deprivation, but near absolute zero, no you shouldn't last long, desperate the bodies heat containing capacities. Unless we assume that the other mix of chemicals does something to compensate that as well.
Finally while that may also apply to radiation, since I'd guess they were made for general emergencies, not just near black holes the hole itself may have been of benefit. Close is different in space, but the black hole was draining the closest star. Idk jack about radiation, but if you want some sort of answer, you can pretend that it was catching some of the damage, plus the helmet, and the short time span-nothing immediately fate.
Maybe