What's Wrong With... Logopolis

The survival of the entire universe relies on an obscure planet full of old men doing sums...

Nothing wrong with that, but why does no-one else know about this? Surely the Time Lords ought to have been aware, or the Guardians of Time. One crazy individual stumbles along and upsets things in a fairly minor way - nobbling just a few of the citizens - and the whole cosmos begins to unravel.

Where's Security when you need them?

Yes, Logopolis is woefully unprotected, despite its crucial role in maintaining the entirety of creation.

Even if the Logopolitans didn't want anyone to know what they were up to, they ought to have put their own safeguards in place. After all, they're creating a model of the Pharos Project - so the concept of failure is not alien to them.

The story starts with the Doctor wanting to measure a Police Box. Why, when he has one of his own? Can't he just take the dimensions of the TARDIS if it's an exact replica of a real box?

If he does need a real one as a model, why visit the outskirts of London in 1981? There are several in Glasgow still, or he could have visited the capital in the 1940's or '50's when there were Police Boxes all over the place.

The plan to quite literally flush the Master out makes no sense whatsoever. The TARDIS might not be infinite but it is vast inside and has rooms, which have doors and can be sealed shut - so there's no reason to suppose that the water would touch him. He is also in his own TARDIS, which isn't going to be affected by the water anyway - and if disguised as something large wouldn't fit through the inner door.

His chameleon circuit is supposed to be working fine, yet it appears as a bush in a vegetation-free part of the Logopolitan settlement. How do you get in and out of it in this form? And why does no-one notice a plant in this plant-free area?

The Master's TARDIS often seems to appear as a fluted column, irrespective of the landing location - suggesting it can get stuck as badly as the Doctor's.

He kills the policeman and Aunt Vanessa -  yet leaves Tegan alone. 

Little time seems to have passed since Traken, yet the Master has his TARDIS time-bubble trap all set up, as well as the scheme to send the Doctor's TARDIS back to Event One, and the whole Castrovalva set-up as the next story begins immediately after this one.

He only ends up on Logopolis because the Doctor's there - yet seems to know all about it having a big secret. He then holds the planet to ransom when he doesn't even know what its secret is or if it's anything of any use to him.

His later blackmail of the universe is just as stupid, as many planets simply won't believe him, and those who do will know that he is hardly likely to kill himself if they refuse to bow to his demands.

The Logopolitans have been working on the Pharos Project copy for a long time - yet the program needed is already completed and sitting in its memory.

Is Pharos the only suitable computer in the whole universe to run it? We've seen vastly advanced technology on other planets.

Why is the entropy field radiating out from Logopolis and not, say from the edge of the universe or its core? Why does it only affect the Logopolitans and not the visitors to the planet? It isn't sentient.

The Master simply stands and watches as the Doctor uncouples the cable, rather than go out and stop him. (It's all too obviously a freeze-frame of Ainley).

How could Nyssa, whose only just learned about them, contact the time-travelling TARDIS? 

Sarah Sutton fails to match the eye-line of the others when the Doctor's falls.

About a third of the universe gets destroyed but, other than Nyssa's quickly forgotten tears for Traken, it's treated as no big deal and never mentioned again.

What a coincidence that the Doctor tells Adric all about entropy, just before entropy attacks the universe.

And finally - why does the Watcher allow billions of deaths to occur, rather than have the Doctor prevent the Master from meddling on Logopolis in the first place?