I farmed enough Dust/Time lost scrolls to summon her, and I did...that's when I started to get worried. I remembered she does a horrific knockback that interrupts your tame. Placing back to tree, I started tame beast, and then the knockback happened. I pop my marco I use for everything:
/use Potion of Speed
/cast Deterrence
/cast tame beast
7 seconds later, the purple warp stalker shrunk, and (immitating Warp Stalkers) went GAHHHHHHHHH. I now have my awesome pet, and I am happy that she, and the other rares I have, will probably throw a party in my stables....*imagines Terrorpene...* ehh, maybe not..
Image:

My precious *pets Purple Warp Stalker*

And after that, I went to get my purple illidari tabard to match ^_^