|–||In the opening TARDIS scene, a boom mike can be seen dipping into frame above Martha's head just before the Doctor says "The sky's a burnt orange".|
|–||It's been raining just before Martha gets abducted by Milo and Cheen, and the Doctor's hair is noticeably wet and plastered to his head as he tries to follow them through the tunnel. As he emerges from the tunnel though (just as their car is taking off), his hair is much drier-looking and blowing around in the breeze.|
|–||So... driving 10 miles to Brooklyn would take 6 years according to Cheen's guess. But to walk 10 miles would only take a few hours, even if you aren't in any particular rush. So why don't people abandon their cars and try to walk?? To underline the point, the Doctor seemingly manages to get from the under-city into the motorway by opening a single locked access door into the lay-by (not a fancy electronic lock, just a standard interior door lock). Has it never occurred to anyone to "escape" from their cars at the nearest lay-by and break out the same way the Doctor broke in? It seems odd that everyone is resigned to just sitting in their cars and seemingly don't ever discuss any possible alternatives.
[Even if there's no way to reach the over-city on foot, surely living in the under-city would be better than being stuck in a cramped, smelly car for decades at a time?]
|–||And why, given the amount of time these people spend sitting in traffic, are so many of them beeping their horns? For example, you can hear plenty of beeping when the Doctor's on the lay-by platform, just before Brannigan rescues him. What good do they think this will do? It can't just be frustration, as they'd be too used to the years of traffic to bother.
[Though perhaps they bought "annoyed" as their drug of choice for the motorway. Exactly like a real British road then!]
|–||Ignoring the implausibility of a human female mating with a cat-based humanoid male to produce 100% feline-looking kittens — what's actually even harder to swallow is that Brannigan resembles an orange shorthair, but one of the children/kittens is clearly a blue point Himalayan. It's impossible for them to be completely different breeds — unless of course Brannigan's wife has been fooling around with another cat..!|
|–||The reason not many people use the fast lane is because "not many people can afford three passengers" according to Milo. Huh? So that means you have to kidnap people? Have you never tried asking nicely? There are a lot of people on the road, so no shortage of willing travellers! Why don't more drivers get together and carpool?|
|–||If the traffic moves so very slowly (Brannigan thinks 20 yards in one day is good progress), how can it be that "in the last half-hour, 53 new cars joined from the Pharmacy Town junction" according to the car-spotting Cassini Sister? Where did so many cars find the space to join the traffic?|
|–||Given that the cars can talk to each other (albeit only to those on their "friends list"), it's straining credulity that the characters haven't worked out via casual conversation that all the exits are closed, no police cars have been seen in 24 years, etc! With nothing to do all day but sit in your car by the CB radio, surely people would gossip a lot more and important information like this would be common knowledge?|
|–||Why would hovercars, possessing no wheels, make a sound of rubber tyres squealing on tarmac when they slam on their brakes? (For example, listen out when the Doctor opens the lower hatch inside Brannigan's car and the car underneath pulls to a halt.)|
|–||When the Doctor is about to jump out of Brannigan's car, while he's talking about hardly knowing Martha, his face is lit up blue in the close-ups, but instantly changes to white light when it cuts to the "through-the-hatch" upwards view. (This happens a couple of times during the scene.)|
|–||Watch out for the Doctor's sonic screwdriver "jumping" from one pocket to another as he traverses from car to car: most obviously, as he opens the lower hatch in the bald white-faced guy's car, he puts the sonic in his right breast pocket. But a moment later when he jumps to the car below, he retrieves the sonic from his left breast pocket.
[After losing one in Smith & Jones, maybe he carries one in each pocket now "just in case"?]
|–||Since it was established earlier that you can't communicate with another car unless you're on their friends list, how did the other car in the fast lane talk to Milo and Cheen's car just before they were attacked by the Macra? OK, the obvious answer is "because they were on their friends list", but there was no sign that they knew each other.
[Maybe there's a special channel for emergencies? You know, standard emergency situations: fire, theft, giant crabs — that sort of thing.]
|–||Novice Hame cuts open the roof hatch on Brannigan's car to get in... seemingly not caring that Brannigan, his wife and kittens will now be stuck in that car with the toxic smog wafting in through the open hatch. Pretty callous of her!
[Won't somebody think of the children?!?]
|–||Besides, how on (New) Earth does Novice Hame track the Doctor? She goes right to Brannigan's car, even though the Doc isn't there anymore, then she makes a bee-line straight to Bowler Hat Guy's car — how did she know exactly where to go? Pretty improbable that it's her feline sense of smell, given all the pollution and smog around the place!
[Though maybe the Doctor is particularly smelly...?]
|–||To avoid being noticed by the Macra, Milo and Cheen turn everything off in their vehicle, including the engines — so how could the car still hover? Shouldn't it have fallen to the ground or crash-landed into the Macra? Before you say "well, the car itself must be made of some anti-gravity material" — earlier on in the episode, we heard Milo himself say "engaging anti-gravs" as they took off after kidnapping Martha, so clearly anti-gravity is an on/off mechanism and should have been turned off along with everything else.|
|–||If the Macra survive on the gas fumes produced by the traffic, then why do they try to 'kill' cars, destroying their only food source?
[Perhaps because they're great big brainless "beasts"? After all, humans depend upon the rainforests but we still hack them down.]
|–||According to Novice Hame, the Bliss virus killed the entire planet in "seven minutes flat". How can a virus possibly spread across an entire planet in just seven minutes? Must have been a very windy day!|
|–||Then Hame goes on to explain that the under-city was "sealed" to contain the disease. Er, it clearly wasn't sealed as there are still people freely entering the motorway from the under-city — Milo and Cheen's car for one, plus the rest of the "53 cars in half an hour" that also joined the motorway at Pharmacy Town around the same time (see above).|
|–||So the cars run on "self-replicating fuel", eh? Ignoring the fact that There's No Such Thing (hasn't RTD heard of the Second Law of Thermodynamics? But OK, this is sci-fi, so we'll let that one slide)... so the cars on the motorway have a basically endless fuel source, but the Face of Boe has to use his dwindling life force to keep the city alive? Why doesn't he send Novice Hame to steal a few cars so he can hook them up to the power grid? (Even if you can't get cars off the motorway, there are still plenty of cars joining the motorway from the under-city as mentioned above — so steal them before they get on the motorway!) Bingo, an unlimited energy source and no need for our favourite Giant-Head-In-A-Jar to do his noble self-sacrifice at the end.|
|–||It appears to be broad daylight when Milo and Cheen kidnap Martha at the beginning (pretty unlikely to have been artificial light due to the lack of power in the city, as we find out later). So at the end of the episode, when the motorway roof opens, why were they so amazed at the sight of daylight?|