After further attemps, it looks like MNP isn't really that big of a requirement, although it can help. Leeching can also work, but doesn't really provide enough healing to be THAT useful.
Dirty Tricks is a big plus for this fight.
You need to stick to Bo Bobbie like glue. I use nerve strike as well, and open with Cheap Shot. Let the next death ray get cast (for a 50% damage reduction thanks to Nerve Strike.)
After that, if Gouge is off CD, use it to interrupt the death ray.
If Gouge is not up, use Kidney shot.
After a kidney shot, let the NEXT death ray through for a 50% damage reduction thanks to nerve strike.
When Bo goes under a shield, get under it with him and bandage. If you are using leeching poison, shiv as well.
Keep recuperate up at all times (with glyph.)
Using this method, you should interrupt most of the deathray casts, and be able to heal up through the ones that you do not/cannot interrupt. I've gotten him to sub 5% twice now and accidentally stood in a final bomb which killed me. Definitly doable, but takes a lot of precise movement and paying attention. A single mistake kills you.
EDIT: SUCCESS! Finished with 80% hps. A good note is when you get close and Max is tossing bombs, you can stand right on top of bo and pop Cloak. You will immune the damage for 6 seconds and can pile on the damage to make sure you beat enrage.
Edited by Rigapples, 03 December 2012 - 05:13 PM.