chiming in late with my experience...I was in the midst of my last semester of student teaching when my supervising teacher delivered her baby early. The school got permission from the state for me to be a paid substitute and resume my student teaching later in the summer. I had already booked my DDs and I on a graduation trip to WDW, so the school hired a substitute for the substitute (me!) so I could take my trip. I finished out my student teaching during the first semester of summer school and they hired me to stay on and teach the 2nd semester.
As far as classes preparing me, no, I don't believe they did. There was a LOT of politics, backstabbing, and kissing up that I was ill-prepared for and it only got worse once I was hired. My 2 regular years of teaching were more about playing a game, trying to not get caught up in the political maneuverings, but I failed miserably and wound up resigning. You are very lucky if you get into a school that doesn't have all the "behind the scenes" that my 2 schools had. Lord, have mercy, I could have written a novel!