Unless, the signs may not actually have been that obvious. We were told in the Dive Medicine Q&A thread by DiveTalk fans that the description of Woodies symptoms were to be interpreted as "Woodie was tired after the dive and it's normal to breath O2 when tired after a dive." Maybe if that is normal for Woodie, the other two wouldn't have notice anything unusual during the hours before they took him to the hospital.
Actually, a number of people said breathing O2 after a dive was normal, and didn't merit a call to DAN. Some of them were regular posters on SB. Maybe you and I are outliers for believing that if it is serious enough to breathe emergency O2 it is serious enough to call DAN. Maybe we need to be sent to the re-education camp -- I mean training -- to learn the pravda way of understanding this incident.