thanks for linking to my earlier reply in one of these threads, now i don't have to repeat myself (mostly)
that said. on the subject of tension, a standard 8mm steel winch cable can withstand upto 25-30 tonnes before it breaks under ideal conditions, however the devil in detail is not just the cable but also the anchor point, example: a single line recovery has the cable (mounted to an 8000lbs rated winch) able to pull no more than 4 tonnes, add a snatchblock/pulley to make it 2 lines and you can double that figure to 8 tonnes, add a another to make a third line and it will go to 12 tonnes, and so on (this has a net benefit of reducing strain on the cable). however if the anchor point you use is not rated to take that kind of strain it will give way (there have been cases where people doing a winch recovery for their 4wd and the recovery point couldn't handle the strain, they ended up pulling the entire front end off of the chassis, including the winch itself.)
having seen gasaraki many times, i wouldn't call it (or any of the creators other works) realistic. believable yes i would call it that, but not realistic
now i'm not saying the firing and retireving cables can't be done, just not at the speeds they (tv, movies, etc) show it happening at (at least not with steel cable, now if they were using something like the recently developed plasma rope or the even newer Dyneema rope, and a new kind of winching mechanism was developed in the next 20 years, then maybe it might be a completely different story)
What you wrote about unwinching is interesting. I still don't think its a problem, because the lines are not shown to be under a great deal of tension (if any at all) when fired. But it was good of you to bring it up.
to be honest all forms of media never get details like that right even if they try to aim for realism. chalk it up to artistic licence or something, but unless they see how it works for themselves they won't be able to portray it correctly