This dive has haunted Jim for over a decade with occasional cold-sweats. What would have happened if my DM hadn’t asked about the air pressure of that diver? I don’t think how close they were to a potentially fatal cascade of events had ever dawned on that diver. As most experienced divers know, it’s cascading events that can go completely sideways, starting like this.
Who is ultimately accountable for assessing the suitability/safety of any specific dive? There are plenty of excellent discussions on a scuba forum about this. In the US context, most of the reading I have done leans towards the responsibility of the diver. In Japan, for better or worse, dive operations probably have a higher level of care than some other nations.