She's a researcher (or perhaps even a grad student with a job offer) before jointing Starfleet. They NEVER say she joined to look for Korby.
The idea of joining Starfleet as a nurse to look for Korby just doesn't make sense. A nurse would have no influence over ship deployments or landing party launches, or even landing party composition. If she were looking for Korby, it would make more sense for her to have hired a private ship, or for her to be working with Federation politicians to influence Starfleet ship deployments rather than just working in one starship's sickbay.