As an example, I'd read an article about timing attacks, so I knew what the author was getting at in the slide about rewriting that loop. If I saw the slide without any background, I'd have been left scratching my head since it doesn't make any attempt to explain the actual issue.
Let us know when the audio is available. I'll keep the slides around until then.
Yep. There's a practical limit to how much text you can put into slides and have them still be useful; I decided that it was more useful to have the recommendations in the slides and the reasoning orally than vice versa.