For me the point of repeatedly going over trauma is that I can only handle small doses at a time before I shut down. Plus eventually we plan to go back to EMDR so the trauma no longer has a hold on me ... we just need to get there.
As far as your breakdown goes- I wonder if your providers want to be prepared. To know what to look; for what might have been triggered leading up to it; and what helped you.
I had a breakdown where I was so overwhelmed and was taken out for work for 2 months, etc. It was a very difficult time. My new providers want to know about it in an attempt to help prevent it from happening again.