I left my job as a psychologist to go on a round-the-world trip. After falling in love with scuba diving and taking a job as a cook on a dive boat in Australia, I called my boss in England to tell her I wouldn't be coming back.

Students would board a boat for a three day trip after two days at the diving school. I was the one who came with their concerns: "Are there sharks on the reef?", "Are they dangerous?", and "Is it pitch black on a night dive?" My psychology skills were put to good use.

Two of the instructors asked me if I would join them on the early one, and I said no. They said the best time to dive was in the morning when the fish are awake and feeding on the coral. They were going to dive. Two of the most experienced divers were also the most competitive. I felt like I wasn't in my comfort zone. I felt bad as I watched them sink.

Thomas takes a break on the boat.

Thomas takes a break on the boat.

They should have come back after 22 minutes. The crew and I were waiting for the water to be scanned. Neither of the divers had taken their digital compasses.

My fear grew as time went by. We tried to keep the potential catastrophe a secret from the scuba diving students. The training dive was canceled after 90 minutes, and the skipper had to explain.

A passenger saw a small glint of silver on the horizon. The divers went into the water. The divers were picked up after the skipper investigated. Without a compass, they were unable to re orient themselves to the position of the boat. They were able to stop themselves from drifting further by wedging some equipment into the coral. There was a watch that reflected the sun's signal to boats.

They were subdued and appeared to downplay the experience, despite knowing there would be a safety review. They were terrified of being in the middle of the open water with small dots bobbing in a wide expanse of blue.

It could have been a tragedy, but it was a reminder of the power and unpredictability of the sea.

I drank beer under the stars and thought about not going with them. I thought about my own novice anxiety, because I felt it was something to do with their experience and their competitive nature. I wondered why neither instructor had taken a compass, given how many times they had talked about safety.

I saw it on their faces – the terror of being in the middle of the open water, small dots bobbing in a wide expanse of blue

The instructors were familiar with the dive site. They were highly skilled but put themselves in a vulnerable situation by going underwater without a piece of vital diving equipment. Being revered on a boat may have made it difficult to stay grounded.

The way I worked with my teams was influenced by this experience. I went out of my way to encourage the voices of new arrivals, as experienced staff members have huge skills to impart, so too do novices. There was a risk. Fresh eyes can be important in a system that feels tired. When I was teaching a lesson on an OB ward, I found out that a student had averted a life-threatening disaster. The medical director and another senior consultant were not present and so they kept quiet. The student who had learned about this rare condition for an exam the week before, and had no idea who the consultants were, blurted out her concern and correctly diagnosed the problem. She might have kept quiet if she had known that she was on a placement.

Bev Thomas on the Great Barrier Reef

‘I fell in love with scuba diving’ … Thomas on the Great Barrier Reef.

Surgeons can be revered like the diving instructors on the boat. Sometimes, they should be revered for their brilliance. Experts can make mistakes, but they are also human. We can't leave it to the inexperienced to wave the flag. There needs to be a culture of openness in the organisation.

I feel a rush of joy when I know they are safe, and I think of those two divers a lot. The brush with death on a boat in the middle of the Coral Sea made me aware of the complexity of decision making. We need to remember that reverence can obscure our vision in life and death situations. I use the life experience I gained from my holiday job as a psychologist.

This week, The Family Retreat is available for purchase. You can order your copy at guardianbookshop.com. There may be delivery charges.