Nick’s introductory voiceover explaining the anomaly isn’t actually said by him until Episode 3.

Connor tells Duncan and Tom that he can’t tell them much because of the Official Secrets Act, so presumably he and Stephen were made to sign it, just later than the other two for some reason.

Connor swears on his poster signed by “Luke Skywalker and Dave Prowse”. Wouldn’t a nerd like him use either both character names or both actor names?

Great line: “That’s the saddest thing I’ve seen since Matrix Revolutions.”

How can a zookeeper afford a huge warehouse flat?

Why is an Underground technician walking the tracks during daylight hours? They usually only go into the tunnels at night after the network has shut down and the electricity has been turned off. A lot of his scenes were interspersed with daytime scenes, which was either confusing or he has a bloody long shift, ‘cause he’s still there in the middle of the night!

Nick tells Connor and Abby that the police won’t prosecute them for trespass. Can you trespass in the New Forest? Isn’t it public land? (I could be wrong here.)

They’re trying to keep all this quiet from the public, yet the military go charging into the Underground station with rifles before the public have been evacuated. How’s that not going to make the Six O’Clock News?!

Great line: Abby (on seeing the giant spider/scorpions): “Does anyone have a really big slipper?”

Two people have been bitten in the neck. Why aren’t Nick, Stephen and Abby wearing some kind of neck protection, even if it’s only a thick scarf?

Why does Helen taunt Nick in the tunnels by calling his name and then hiding?

Abby and Stephen say they need Connor to identify what’s in the Underground. Connor arrives and says the centipede is probably an arthropleurid. Nick then brings Stephen up and, without having heard what Connor said, tells everyone Stephen was bitten by the arthropleurid. So what did they need Connor for?

Before going into the hole into which the arthropleurid has burrowed, Connor takes his shoulder bag off. As Nick and Ryan head into the hole, Connor waits behind them – with his bag back over his shoulder.

Nick tells Connor and Ryan to put turpentine on their clothes to keep the bugs away, but it doesn’t put the arthropleurid off attacking them later. Maybe they should have put a bit more on?!

Nick tells Ryan not to shoot before they’ve got the venom. Wouldn’t it be a lot easier to extract the venom if it’s dead – or does venom go off really really quickly? Of course, if they had waited, it might have all been fried off!

Stephen makes a remarkably quick recovery. He’s dressed and sitting up and reading before Abby has even had a chance to change out of her boiler suit.

Why is Nick watching the anomaly alone, with no military backup? Another arthropleurid could come through at any time.