So the Doctor had regenerated. The Master didn't like this new appearance much. It was…acceptable. The less acceptable was what the Doctor admitted about rescuing him. The Master who'd just begun to hope and love again learnt that he was rescued only to stand in for a companion the poor Doctor had lost until finding a future proper companion. The lesser acceptable was to also learn he can't leave the Tardis and he was programmed to be the perfect maid-servant.
He has never ever felt so betrayed. Not even at the Axons' time.* By the way the Doctor has always been the one who stab both his hearts. While he wanted to give him half of the universe and be with him, the Doctor made him believe he agreed and changed sides to leave him at the aliens' hands. Yet he, the great Master, fell into the trap every. single. time. And kept loving this damned Doctor. Until the love turned into hate. It couldn't be helped. The Master was just tired of loving someone who wanted him dead. So he tried to kill him. Many times. All failed. And here comes that obnoxious rascal bringing his hope back to life to then put it down.
Still now, he has to choose between a maid-servant life and a certain death. Death is the only thing he hates more than the Doctor. So he has already made up his mind.
Alison POV
As if by magic, they had managed to escape the soldiers. Both were out of breath.
"So these are samurais? I thought they…kind of stood together…that they're supposed to help each other."
"Well as you saw it…they're not really…like in history books…in reality…samurais did all they were able of…in order to get promoted or…get the glory. Even beating or slaying…their own comrades."
"That was indeed hazardous… and strangely…I enjoyed it." She smiled.
"At your service." He smiled back.
"So…how about going back to the Tardis before they reach us?"
"Agreed."
Master POV
In the end, he has more reasons to do this. He hated Alison, as any of the companions his Doctor ever had, he hated this humiliating life and the Doctor hated him. So, the Master left the console, walked slowly towards the door, opened it and went out.
Alison POV
The sky was getting dark. Enormous clouds were gathering while a loud thunder broke out. Lightening tore apart.
"We should hurry up Doctor." She warned the one who was admiring the Mother Nature's show.
"A minute Alison."
"You may change your face but I don't think you're lightening-proof! So let's go back before you get an accident!" She said before taking the Doctor away.
*Claws of Axos episode