I can read Mandarin. I have benefited reading articles from this board for long time. Never post. Since I can read Mandrin, I did a little search on the internet and found that it is uninformative, even in Mandarine news. I found following though.
1. The one that was injured, was during searching those two victims and there is no mention of what kind of injure.
2. Half tank of air remained. No mention which half.
3. No mention of any bad air, may be they did not check the content of air remained.
4. The investigation said they were having Air Embolism.
5. Friends, of these two victims, "guess" in their post that they were having Narcosis.
6. Their diver friends in HK said, in their post, that it is doubtful, because the lady is a "diving instructor" and the gentelman is a "Rescue diver". Narcosis and abnormal ascenting should not happen simultaneously on both of them.
7. They are both very good people and their friends love them very much.
Sorry for not helping much.