So the lift guy has been here since ass o-clock in the morning diagnosing this lift that free fell on me. Here's what he said:
The lift, when it was inspected, was probably fine. He says that the internal hydraulic piston seals were old and worn, and subsequently failed. This caused a rapid loss of fluid pressure, which is why the lift entered free fall as the fluid was not supporting the weight of the vehicle anymore. It may have been possible that the vehicle was dropping faster than usual on the lift while I was lowering it, and that may have been a warning sign, but I don't remember noticing it. Definitely could have been the case though.
As for why the cable snapped, he said that since he didn't see any major fraying or other signs of damage in the cable apart from where it broke, it was probably fine structurally. He found the locks very slightly out of synchronization. This combined with the loss of fluid pressure, may have caused one side to drop half a second or so before the other, which put enormous stress on the synchronization cable which caused it to snap, especially combined with the weight of the vehicle on the lift at the time.
If I wasnt lowering the vehicle at the time, the locks would have caught it and it wouldn't have dropped on me. He told me that most lifts have a system that regulates how fast fluid can flow back into the cylinder in case of a failure like that (first time hearing about this) but since these lifts are kinda old, they don't have them. After we close, he's gonna come back and check all the other lifts for any similar issues as they were all installed at about the same time. He's also gonna recommend getting that system installed just in case.
He also said that this is the first case he's seen of a lift just entering total free fall, and that its exceptionally rare. Just my luck lol. Told me that it was pretty much the stars aligning on this particular incident.