I've started playing a lot of Tome recently. I am playing only Nightmare difficulty, Roguelike mode. (Hardest possible from the start. I haven't managed to make it to the East yet).

Currently I am playing lots of Archmages. I started out playing Dwarf archmages for the HP bonus, but after going online and reading Mex's guide, I've been trying the Shalore Archmage. (It seems way squishier than my Dwarf archmage/vulnerable to 1 shotting before I can put shields up! But the crit damage is a lot higher/bigger shields, which I guess is essential later and on even higher difficulties).
Anyways, my last three good runs (into the ~20s in level) have ended when I had the bright idea "Hey, those Ziguranth patrols that are running around have good loot. Lets try fighting some". Usually I beat several of them fairly easily and think everything is great, but then in the next one I'll walk around a corner and get 1 shot by some halfling slinger hero or something.
So what do you do? Do you try to fight the adventuring patrols as some point(s) in the game, and if so when? Do you avoid them due to risk? Should I just be more careful about casting Arcane Eye and shielding before I encounter them, or should I try to avoid them completely?
Thanks!