You automatically fail.
Probably. You'll need +IAS mods (increased attack speed) on weapons as a general rule, but once you get onto LoD, there are a great massing of Runewords that give both. Alternatively, you can socket something with a Shael, which gives IAS, I believe, as SRL has said.
Yeah, that's why people try their hardest to find an Infinity. I may not have all of my Ber runes left, but I'll keep making them when supplies are available. If you are having resistance problems, equip a Fortitude, El Sol Dol Lo/4Os Armor with defense at 450+ (I've got some of those for you). I also have a Rockstopper Sallet with a Tal socketed, so it should cover your resistances and is good with its faster hit recovery.
What are you merc stats?
Difficulty?
Aura?
Helm?
Armor?
Resistance in Hell?
Terror Keys == Hate Key, but two Terror Keys == a Destruction Key.
Ahh, that would explain your absence. Also, I have some 4Os armors, but not Archon Plates. Dusk Shrouds are also good substitutes, but a high defense one of those are difficult to find.