Doctor Who: 10 Times The Doctor Shouldn't Have Bothered With Mercy

4. Mercy On The Family Of Blood

The Tenth Doctor's second entry on this list is also from series three. The darkest story of the Tennant era saw The Family of Blood chasing the lives of a Time Lord so they could live for eternity. The Doctor, in his infinite wisdom, decided to hide away from them using the chameleon arch to become John Smith. Acting as a school teacher in an English village, in 1913, he lived a human life, falling in love with a nurse and forgetting everything about the consciousness that lay in the Fob Watch - aside from the dreams he has. Ultimately, The Family find him and put the entire village in danger causing a war to begin one year early. They take human forms and form an army of scarecrows. Martha does her best to convince the stubborn human form of The Doctor to finally return and when he does, it is revealed that our hero could have swiftly defeated them in the first place. It makes you wonder why he would put lives at stake just to save himself from defeating the enemy - even if he was cruel in their dispatching. Also, poor Martha. She was never treated well by Ten, who was still hung up on the loss of Rose. Here, a qualified doctor ends up having to scrub floors and take racial slurs just to keep an eye on his human form. She deserved so much better from him.