Writer Eric Saward makes his Doctor Who debut with The Visitation, and already some of the hallmarks of what was to come in Doctor Who for the next few years are visible. First up: conflict within the TARDIS.
The very first TARDIS scene picks up midway through an argument between The Doctor and Adric, with The Doctor admonishing the lad for his hijacking of the TSS machine during the previous adventure (this was another reference to the most recent adventure that producer John Nathan-Turner loved to put in to each story at the time to better link each story together). Once Adric goes off for a sulk, it's time for Tegan to have her turn, and it's her spat with the Doctor which drives everyone out of the TARDIS and into the story proper.
Two arguments in two minutes does not an harmonious TARDIS crew make, and yet Saward seemed to think that such things made for interesting television. At least here, the differences don't last long and the characters' relationships don't hold back the story, but it's amazing to see what will become a problem in the future for the show have its roots so early. At least Adric breaks the stereotype by being the one to sprain his ankle (and unconvincingly, at that) as opposed to the female companions always begin the ones taking the hit.