Funny story for you guys. I love Mileena, and decided to practice her as possibly my secondary, hadn't decided yet. I saw this thread and decided, well now is a good as time as any. Unfortunately for me, I watched the video once and misunderstood the ender, and though it was the B212+3, and kept trying to land it after a run cancel. After a few hours practicing a day trying to land this, for a couple of days and only landing it once (somehow!) and never being able to replicate it, and reading some of the posts in this thread that people were getting it consistently, I concluded that ALL MILEENA PLAYERS HAVE GODLIKE EXECUTION and I would be picking a different character to pick up.
Gave the video another watch however, and realised my stupid mistake. Landed it first time, and having no trouble getting it consistent now. Lol @ myself. Looks like I'm joining the Mileena team now \o/