My pet doesn't like the arena.

Heres a few screen shots and i had to move around a bit to get him to move. (without argro'ed the boss)
But if you look closely, the pet has trouble with going through the gate.

an observation:
I might not try arena again since bosses are to hard for me even with decent gear...to many pots and revives. my team easily gets wiped out...only way I can see this working is if the boss doesn't reset.

you can see the bosses feet..top center of the pic
Attachment 106082


moved a bit more away.
Attachment 106083

but if the match is started..the pet will get stuck on the spikes. So i had to move around to get him into the arena with me.
Attachment 106084

i took the pics after i died a few times, but the pet can get tangled at the entrance..so if he's stuck he cant help attack the boss. or use arcane ability.

that happens to my pets too.

I just dismiss my pet, then summon them

Yes known bug. If your pet gets locked out re-summon them.

Maybe Abaddon is just scared or out of pots and Ankhs.

Hug the arena walls when u enter, make sure your pet follows you and you're all set :)