Doctor Who Season 7, Episode 4: The Power Of Three

Another solid episode this week. I'm really enjoying Season 7 so far, much more than last season, They seem to be on a roll. Let's hope they keep it up.

Spoilers Ahoy!
The plot: Amy and Rory are going about their everyday lives at home, away from the Doctor. One morning millions of small, featureless black cubes appear all over Earth. The cubes are invulnerable and present no apparent danger. A year goes by and the world forgets about them, which is exactly what the cubes want...

• In the past three episodes the title sequence has had an unpleasant yellowish tint to it. This episode it's got a definite purplish cast. Plus this week there's more detail in the "lightning hits." Odd.

• The "textured font" theme continues. This week the Doctor Who logo has a fitting cubical texture (although if you didn't know about the cubes it could be easy to mistake the texture for argyle!).

 • It's the welcome return of Brian Williams, Rory's dad! Sadly, this will most likely be the last time we ever see him.

• I thought the "cube Invasion" was a brilliant idea. Send a bunch of inert cubes to Earth, wait until the population gets used to them and ignores them and then strike. 

• "Within three hours the cubes had a thousand separate Twitter accounts." I have no problem believing that would really happen!

• Rory: Right, I'm due at work.
  The Doctor: What? You've got a job?
  Rory: Of course I've got a job, what do you think we do when we're not with you?
  The Doctor: I imagine mostly kissing.

• Amy tells the Doctor that she writes travel articles for magazines. When did that happen? Is she no longer a model?

• It was a nice touch (and quite a surprise!) to see the UNIT troops being led Kate Stewart, daughter of the Doctor's old collegue Brigadier Lethbridge-Stewart. I liked her character a lot and hope she pops up again. One thing though: Did the Brig ever once mention a family? I freely admit I'm not an expert scholar when it comes to the old episodes, but I don't ever remember him saying anything about one.

UPDATE! A loyal reader has informed me that the Brig talked about his wife in many episodes and she actually showed up in one. Also, Kate Stewart is not a new character, as she's appeared in several direct-to-home video side projects. Well, there you go then!

• What was with the twin hospital orderlies with the cube shaped holes where their mouths should be? I figured we'd see them firing cubes out of their "mouths" at some point, but it never happened. So why did they look like that then? 

• The conversation between Bryan and the Doctor about companions was very well played.

• The scenes of the Doctor unable to be patient were well done, and made perfect sense. Think about it: A Time Lord would never develop patience. He has a time machine, for poop's sake. He never has to wait for anything. If it's June and he can't wait for Xmas, boom, he flies the TARDIS to December 25 and he's there. No inconvenient and interminable waiting.

• Did we just see the return of fish sticks and custard?

• Amy says by her reckoning she and Rory have been traveling with the Doctor for ten years, although far less time has passed on Earth (because they have adventures in the TARDIS that last weeks or months, and the Doctor brings them back home minutes after they first left). I don't think this phenomenon has ever been explored on the show before now.

I'm not quite clear on how she's measuring the ten years though. Is she starting it from the very first time she and Rory traveled with the Doctor, in The Vampires Of Venice? Or is she starting from their wedding in The Big Bang? Or from the time the Doctor "died" and gave them a house?

• Classic Doctor Who:

The Doctor: Seven, seven. What's important about seven? Seven Wonders of the World. Seven streams of the river Ota. Seven sides to a cube.
Amy: A cube has six sides.
The Doctor: Not if you count the inside.

• Eventually the cubes reveal their true purpose: exterminating the "human contagion" before it can spread throughout the galaxy. They do this by using an electrical pulse to stop the heart of any nearby humans. A cube also stops one of the Doctor's two hearts. Lucky for humanity (and the show) that the cube only stopped one of his hearts. I suppose you could argue that the cubes only had enough power to stop one, but it still seemed convenient.

• The Doctor limps along painfully for quite a while with only one functioning heart. Finally Amy uses a defibrillator to shock his stopped heart back into beating. Sigh... this is an old, old, OLD mistake that crops up over and over and over again in TV and movies.

Defibrillators do not work this way. They are not human jumper cables. They are useless on a patient with a flatline heart rate (known as asystole). They are used on patients suffering from ventricular fibrillation-- a heart that is flip-flopping around in the chest with an irregular rhythm. A defibrillator, as its name suggest, stops the fibrillation; in other words restoring regular rhythm to the heart. It can also be used to treat ventricular tachycardia-- a heart that is beating too fast. A non-beating heart cannot be "jump-started" by a defibrillator, and can only be helped by CPR or intravenous medication.

How this inaccurate trope got started and why it persists, I have no idea.

• The Shakri looked a lot like the Anakin Skywalker from Return Of The Jedi (the original version, not George Lucas' revisionist Special Editions.

• The Doctor eventually saves the day (and one third of the human race) by reversing the polarity of the neutron flow or something and restarting the hearts of everyone who was killed by the cubes. It seemed like quite a long time elapsed though between the time everyone's hearts were stopped and when they were restarted.

So how long could a person survive with a stopped heart? I wouldn't think very long. If your heart isn't pumping, then it's not carrying oxygen to your brain. The human brain can only survive for a few minutes without oxygen. I hate to nitpick too much, but all those people whom the Doctor saved by restarting their hearts are most likely going to be brain-damaged.

• Just an observation: In all of this season's previous episodes no one has heard of the Doctor, as if he's been erased from the universe. That didn't happen this week, as Kate Stewart definitely knew him.

• Next week, the Ponds say goodbye. I've been trying to avoid spoilers all summer; nevertheless I have a pretty good idea of what's going to happen, and I don't like it. It's gonna be hard watching the next episode.