The Mirrorball Man wrote:
Liz Shaw simply stopped showing up to the lab, and Jo showed up in her place, so, Liz didn't even get an exit.
Which makes me think... What was Jo's deal exactly? What did UNIT see in her? What was her job description? Did the Brigadier spend time interviewing young women who could convincingly act like ten-year old girls, ask stupid questions and get into trouble on a daily basis?
<lifted from wiki>Apparently, she gained the assignment to UNIT because her uncle, a high ranking civil servant had "pulled some strings"</lifted from wiki>
I seem to remember her saying she had lots of "Agent" training and was good at picking locks.
I don't remember her having any usefull skills in the episodes though.