I don't know who the diver was, but he was doing a solo dive on the Monitor to what...220ft to the bow to get some photos? There's a very small contingent of people I'd trust to properly execute a dive like that. When he was dropping down he was bicycle-kicking and waving his arms about like crazy (looked like an OW student). Then, because he was futzing with the camera, he switched to O2 at his 70ft stop instead of 50%.
I thought it was amusing that many people at the conference were very anti-GUE, yet...the standard GUE gas-switching procedure would have prevented this incident (and many others). Definitely not trying to turn this into a GUE/DIR/whatever argument, but...I did find it somewhat amusing