Capture it while it's fresh, then move forward.
A few minutes, while it's vivid. Each note saves itself, kept with the rest of your preparation. You won't catch everything, and you don't need to.
What question caught you off guard?
Which answer would you give again, better?
Which story landed, or which one were you missing?
What did you learn about the room?
Which room was this? optional
This debrief is yours, free. It saves itself as you write, kept on this device with the rest of your preparation for this preparation.