My anecdotal experience is that if you kill a critter on the EVEN rounds of your berserk, it will carry over to the next combatant. So if it takes 2 rounds to kill each critter your berserk will just keep on keeping on. If I continue on to a new combatant and kill them the first round, berserk almost always ends.
Know your enemy. Once you get them figured out a bit you will know how to deal with each specifically, be it feint, ambush, mstrike, or berserk. This also is a big deciding factor in the arena, what lineup you get. If all my champions are brawlers, I stroll through it like nothing, get me caught berserking on a turtle for 9 rounds and I'm boned.
Also, if it wasn't mentioned. HAVE DEEDS! They will prevent spell loss from death in the arena.
"Hi, my name is Ososis and I'm blaming my shitty life for being such a fragile, soy drinking, emotionally unstable loser. My triggers are: Red reputation, ANY mention of MacGuyver and being called a fragile, soy drinking, emotionally unstable loser."