7. The Master, Logopolis
The Master knows that the Doctor is going to pilot the TARDIS to measure a police box off the Bedford bypass, because theyre both Time Lords and in many ways we have the same mind. The Master materialises around it first, disguising his TARDIS as a police box. He then flies his TARDIS around inside the Doctors one purely to open the door and chuckle at a confused and terrified air hostess. Also he kills two people who approach the police box by shrinking them and leaving them to be found. The Master knows that the reason the Doctor wants to measure the TARDIS is to repair it on Logopolis, which involves monks chanting equations. The Master follows the Doctor to Logopolis thus revealing that all his activity near Bedford was merely done to make the Doctor wary, which he is, but not about that in order to kill a monk and ruin the equations so that the TARDIS shrinks with the Doctor in it, and the Master can chuckle and say At last Ive cut you down to size. Literally everything that hes done so far in the story is purely to achieve this zinger. His actual plan is to harness the power of Logopolis - using pure maths to alter the physical universe by suppressing the chanting that forms the equations. The only problem with this is that it accidentally starts off a chain of events that will destroy the universe. Still, so worth it for that pun.