It's either teleport runes or movement infusions, one or the other. As a general rule, if you don't have (at least) one of the two you deserve the death that's coming to you
Or a psychoport torq or whatever, I guess. Teleportation amulet. Something to get yourself out of dodge. Lightning speed probably would have managed. Remember to have one next time you hit DF *sage nod*
Mobility is really
very important, heh, especially when you're up against somewhat stacked odds.
Anyway, barring the crash that sort of fight is very doable, just have to figure out a way to separate the enemies and defeat them in detail. Teleport's particularly good when you're dealing with boss monsters, as they'll track you across the level so it's easy to pull them from whatever supporting monster pack they were stuck in, but movement infusions'll usually work, too.