If you get engaged in open space with nothing to duck behind, and there are Priests,
run the fuck back the other direction at an angle until you find one. Whip out a Teleport scroll if you have it and you're cornered (if you're not cornered nor about to die, then don't waste it), or a Blink scroll to instantly get out of Priests' LOS, or a Fog Scroll to block Priests from seeing you (they can't Smite if they can't see you!) as you run away. Watch your Minimap; the little blue dots are up-stairs, which you should be maneuvering towards as best as possible, and the purple ones are down-stairs, which will also work to elude your pursuers
if no up-stairs are handy, because being forced to go downstairs via too-hard opponent is usually VERY DANGEROUS and if this happens make it your goal to locate the other two up-stairs on the lower down floor AS SOON AS POSSIBLE.What you should
never ever do is fight Orcs in hallways with Priests standing behind them, out of your reach, smiting you over and over for free. Instead, either:
* Lure the Orcs to a corner so that the Priests have to get really close to you in order to even see you, putting them in your Melee range, or
* Aggro the group of Orcs so that they start wandering the dungeon for you, take the stairs back up, find a seperate stairs down and then hunt the Orcs one by one through the dungeon as they spread out and separate. Priests lose a fair amount of their threateningness once they have no allies to hide behind
Among other strategies, but I'm sure you'll find those two as the most practical.
If you're playing a Mage, too, do note that Priests cannot smite if they're Confused via Mephitic Cloud, nor can Wizards cast spells. Firing the cloud at a group of Orcs and then running is a great escape tactic, and firing at a group of Orcs in a tight hallway and then running is even better and has a high likelihood that some of the confused Orcs will kill each-other for you off-screen, awarding you the experience points for it. Straight melee, on the other hand, has the advantage of being able to mow them down in one or two hits each, as Orcs are extremely glass-like and die easily, unless of course they are Warriors, Knights, Warlords, Urug, Nergalle or Saint Roka. ^^ Hehehe.