Eliot has indeed lived through his tussle with Mephisto.
What an interesting one it was, too. After reading of Bishop's demise, it reminded me to do what I prefer to do on level 3 of the Durance. Run! Run as quick to the left, as I can, ignoring any ghoul lords, or whatever's there, into the lefthand side room. I'll take out whatever's in there, and stake my claim to a safe haven. If anything follows me from the area I just ran past, I'll deal with them, too. But, the main thing is to avoid the scary confrontation with the Council. I've died too many times to them, and it's just not worth it.
So, after I did my run, I was pleased to see only the Boss council guy in the room this time. However, I thought it curious that ghoul lords were coming into the room. I later found they were Extra Fast. More like Flash on speed, it seemed. AND!, the next thing I see, with meteors and firewalls everywhere is Mephisto herself charging into the room. I have never seen that one before. Usually, I have to go draw her out. I have no idea what happened, but I was quite startled, and ran for my life, to where I would usually go to root her out. That's when I noticed those ghoul lords were Extra Fast. They were so hot on my tail, I barely could get a TP down. Not sure how the merc didn't die in all this, but we made it to town. The strategy worked well, as when we came back, we were able to pick off most of the ghoul lords, without attracting Mephisto's attention, who was seemingly taking a nap in that room. The merc didn't survive this strategy though. But, Eliot and his summon sidekick, and a protective barrier(rinse, repeat), took Mephisto down. A Demon Limb tyrant club is not a bad drop. One of the weirder Mephisto battles, for me, though.
I had run Lower Kurast a bunch of times, but couldn't even do it as much as you did Skunk. I gave up a little over 200K. A bunch of merc deaths later, and I'm less than 100, now. So, I may do some more tomorrow. I've had enough for one day. For sure, if I still live, I'll pass him tomorrow. I should probably quit while I'm ahead. But, beyond cash, I'd like one more good rune from Lower Kurast. I got an Io and Amn, but that's it. So, my goal is one more good one, then I think I'll call it quits.