You can have conscious sedation, which I suspect was used. You are not intubated, you just don't feel pain, can react to orders i.e. assist in movements and you are only sedated, not unconscious. It would prevent panic, make them very easy to manoeuvre and allow them to turn, pull, walk etc.
Its usually Versed, sometimes a mix of a few other things. Used very widely as it is very, very safe. Its no accident that the diver who did the medicals is an anaesthetist.
These details will come out later, in a book or an announcement. IMO