Honestly, I can't tell what will happen in BCT, but I can tell you what I do know about the platform jump.
I went to a USMA camp and we were able to jump off of the 30 meter platform. The trick is to stay stiff and hit feet first... the hardest part is taking the step off, then it's over relatively quickly. Chances are that you will touch the bottom of the pool (which is good, because you'll be able to kick yourself up to the surface quicker).
I think we have to do it in gear, which is something I have never experienced off the platform, but from what I do know regarding swim team/life guarding, it will make it much more difficult.