Either disable PvP in pit of undying or make it so that people can't attack you while you are in the pit fighting a boss.

Last night I had a Berzerker Grab me every time I started to fight the bosses, This caused the bosses to kill me while he was holding me.  Because he was not actually killing me he wasn't going negative karma, he would only go red for 20 seconds.  I swapped servers and there was a striker doing the exact same thing.

Don't get me wrong, I am all for PvP, but that is just griefing for the sake of griefing.  

yes the Pit is one of the zones where pvp doesn't make any sense at all tbh. 

I didn't even know you could go there with other people.  Does that mean I can bring a group?

That's just bad game design