The response time of 20 minutes was a performance target set some years before. Unrealistic, considering that the pilot might actually be asleep when the call comes in (although he wasn't in this instance).
I was very surprised that wearing of flying helmets, rather than headsets, was not seen as a priority, especially as it was a night flight when ambient temperatures are lower and personal comfort shouldn't have been a major issue. Complacency a factor in personal survival issues?