Hi Taryn!
It is helpful to think of intragenerational mobility as being over a lifetime. In this case, the question is talking more specifically about the event of being fired from a salaried job and moving to a position with hourly pay. As an event, this is vertical mobility. Intragenerational mobility is more concerned with the movement through society over an entire lifetime, in this case there is still a possibility that the individual regains the salary that was lost in the future, so it is more difficult to determine intragenerational mobility here.
Hopefully this helps!
Taylor