This is very different from the usual fare.
A little dark speculation.
Thanks to Megan for clearing the thoughts.
Thanks to Dani for letting me ruin her headcanon.
Disclaimer: I don’t own Doctor Who. Or the brilliant, nuanced, fallible characters.
Broken soldiers seek mending. Some cannot cope with the civilian life. Some become apathetic or drown in drink. Others seek a new fight or a new cause to follow.
The Doctor found Rose.