Really? [...] I seem to recall getting the 9th level halfway through UC
Yes, I got to level 9
in the UC, but I really wanted MVm before I hit the first demon. I was afraid that if I had to use medpacks while fighting demons, my berserk would run out (I was really paranoid at that point).
I really assumed this would be harder (Spider's Lair spawned over the Vaults in my run) but I never practice the vaults, so I'm surprised to hear that you can just corner shoot everything.
I almost never took any damage in the Vaults. Barons would be lured by stuff dropped by other dead barons, and if I ran in place long enough, the Arachnotrons would come too (sometimes I just rushed in with the LS after the barons were dead).
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This isn't true. In my run I got hit while I was on 100% HP with Iro 4 and about 9 armour (TaN 3 + Modified Red Armour) and it left me with about 20% HP. Iro 4 puts you on 18 HP, and his average damage is 21 (max is 36) so if I went in there with 200% HP even a really unlucky roll wouldn't've killed me.
You are correct, I didn't account for 200% hp. But I think my original point still stands - he will get you down to 100% eventually, and then all it takes is one rocket to kill you.
Theory: 36 max damage - 7 (angelic) - 3 (TaNx3) = 26 max damage > 18 hp (Irox4)
Practice:
You use a large med-pack. You feel fully healed. The Cyberdemon fires! You
are hit! Your Angelic Armor is damaged! You die!... Press <Enter>...And my armor ended up like this (I'm pretty sure it was at 7/7 before the hit, but who knows):
[a] [ Armor ] Angelic Armor [3/7] (29%)