Colossus targeting

I'm at my 6th attempt at this fight for this patch in Act 2 Cruel.

Every attempt was going fine until the Colossus moved either the first or second time. After that he was untargetable and I eventually either died or just hit "respawn at checkpoint" after getting frustrated.

Could you just give melee characters some option to skip this until you've actually resolved the fight? Week one took like 15 attempts with my warrior.