Alexa has turned into Walter White | Heisenberg.
If you don't know the reference, it's Bryan Cranston's character(s) from Breaking Bad, a TV show that aired on AMC for a five years. Most people know the show; I was late on the chemistry bus to watch it, so 2 years after it ended, was when I started binge watching it.
If you haven't seen the show, Amazon has the complete series on DVD for $59.93 right now. It's about $40 cheaper than buying all the seasons separately (between $14.99 & 24.99 each season, depending on season) and streaming it, so if you have a disc player, it might be worth it.
Anyway, the 'one who knocks' is a reference to season 4, episode 6. It's when the cards start falling for real and people realize there's something deeper going on, then a chemistry teacher bringing home a little extra cash during his cancer treatments.
I should see if I can start watching the series again; it was actually pretty cool.
And on a side note, I had used some of the monologue from the scene as a ringtone for someone I used to work with. It stemmed from a joke - we had a locking door in our office, and a client came knocking on the door one day. There was a doorbell at one point (one of those wireless contraptions where the bell can command strip to the door and the receiver is somewhere else) but the client didn't bother ringing. All she did was yell, very loudly, "knock knock!". It was a good thing I was in that part of the office, or no one would have heard her. Yes, she yelled it and didn't physically knock. She yelled a few times and I opened the door, to have her ask me if I had a phone number for someone in the building. When I told my co-worker this story, he laughed so hard because you can't make this stuff up. From that point on, it became a running joke, and I put the monologue on my phone. Yes, I'm crazy. You had to be there.
So, without further ado, I need to prove why Alexa has turned into a meth maker, or I seem nuttier than ever.
Cheers;
See also:
A similar doorbell to what we used: Honeywell RCWL105A1003/N Plug-in Wireless Doorbell