Let me just say as interesting as this was, it would have been sooo much more interesting if The Master was the Timeless Child:

• Why is The Master unstable / evil? He subconsciously remembers all the experimentation done on his previous incarnations as a youth and he's now broken mentally.
• Why has Missy's character growth been undone? Finding out that he was betrayed by the Time Lords for a second time drove him to find revenge.
• How does he keep returning from inevitable demise? He has unlimited regenerations.

A friend on facebook pointed out after my earlier comment that purchasing the episode on iTunes would be better.  Here is my response:

I don't disagree, as a matter of fact I paid for the entire season on iTunes weeks ago.  

I feel there's a social contract: I watch the commercials, pay the fees to my cable company and BBCA shows me the entire episode, at the least the first time it's shown. I'm not anti-commercial, I'm anti-editing. I'd have no problem if they had to add 30%-40% to the run time to add the commercials since I know they need to make money. But to me this is bait and switch. You need to pay either through more commercials or buying on iTunes to see it completely.

I wouldn't have watched it today if I knew that I'll just be rewatching it tomorrow to see what wasn't shown on the first viewing.