Time Lord/Headscratchers

I know TARDISes are bigger on the inside, but...
How would Tohno Shiki be able to enter his TARDIS (i.e. a knife) when the entrance is several times smaller then he is?
 * The entrance is full-human-sized, its just as small as a knife-blade. I assure you, it makes perfect sense in twelve dimensions.
 * The Doctor Who Expanded Universe has a Spaceship Girl TARDIS. Somehow she kind of opens up to form a decent-sized entrance, so people her size or bigger can walk right into her. It's in-universe High Octane Nightmare Fuel. So, the upshot of this is that probably the knife would not, when opened up, look like a knife.
 * The same way you can step through a hole in a postcard. (If you don't know how to do this, look it up).
 * More Nightmare Fuel when you realize it involves cutting it up.
 * If you were to open a hole into the tardis from the outside, what would happen?
 * You would have a hole in the tardis.
 * What happens if you put a Portable Hole / Bag of Holding inside a Tardis?
 * You would have a Portable Hole / Bag of Holding in the tardis.

Why is the Warden's TARDIS Superjail?
Superjail is a series of buildings and made into a volcano. Shouldn't Jailbot be his TARDIS?
 * Because even if then the jail is still bigger on the inside.