In "Arc Of Infinity", the Doctor was sentenced to death by the ruling council because somehow an anti-matter creature had formed a bond with him which it was then using to get access into the matter universe. This would have caused the destruction of the entire TV universe.
No more 'My Mother The Car'!
Commander Maxil was in charge of the detail who was guarding the Doctor during his death sentence. And at one point, he even shot the Doctor!
Nothing like trying to hurry things up......
I would think the Doctor's biological imperative saw elements in Maxil that would be useful for the next incarnation. However, if personality quirks do factor into the decision, then it could be argued that "Nature" made a big mistake. The resulting incarnation, played by Colin Baker, was short-tempered and insulting at first, and in his short time in the Universe, the Sixth Doctor didn't improve his demeanor very much.