Theory:Doctor Who television discontinuity and plot holes/Planet of Giants


 * The Doctor suggests that the fact that the pipe leading to the lab smells of chemicals means that it is safe to climb, seemingly not allowing for the fact that lots of chemicals are harmful - such as DN6.
 * Reasonably, it would not have been too hard for the Doctor to recognize that the chemicals he smelled would be safe.


 * The miniaturized TARDIS crew never interact with the other characters in this story, because, as the Doctor points out, the 'giants' will be unable to hear them, as their voices will be on a different wavelength. So why does the Doctor later suggest using the telephone to try to call for help?
 * He's getting desperate and hopes that he was mistaken about what he said before.


 * Even if the crew are unable to communicate over the phone, the phone call could have the desired effect of arousing suspicion.