Oh, yes. That one, too... if I'm not mistaken, that's the first Who serial I used to introduce my Dad to the series.* He was hooked right away, and he "got" the character of the Doctor in a nutshell, saying something like: "He's the hero, not because he has any special power, but just because he has more experience than anyone else..."

Now that I know my DVD player actually works, I'll have to upgrade from the VHS copy of Tomb that I have...

*(I made a concerted effort not to start with a Tom Baker serial, because, in America, Tom is in full Saturation as the Doctor, and I wanted to disabuse my father of that notion. ... I also made him wait between watching episodes, to give him time to wonder about the cliffhangers, and squirm, a bit) ;-)