Last Breath (2019) Timeline Explained – Every Event in Order

The Bibby Topaz vessel's dynamic positioning system failed in rough seas, causing the ship to drift. This pulled the divers away from their worksite and placed extreme stress on the umbilical tether that supplied their breathing gas, communications, and power. When the umbilical snapped, Lemons was left stranded 100 meters below the surface with only his emergency backup gas supply.

Foreshadowing: The film establishes early on that the divers were entirely dependent on the vessel's systems while working at extreme depth.

• dynamic positioning failure
• umbilical snap
• diver stranded
• North Sea diving accident

Lemons survived approximately 30 minutes despite having only 5 minutes of breathable gas in his emergency cylinders. The documentary suggests that the cold North Sea water and the specific heliox breathing gas mix with high oxygen partial pressure were contributing factors that may have extended his survival time, though the exact reasons remain medically unclear.

Foreshadowing: The documentary hints early at the extreme conditions divers face at 100 meters depth.

• survival
• cold water
• hypothermia
• heliox breathing gas

The umbilical is a critical tether connecting the diver to the surface support vessel, delivering heliox breathing gas, heated suit water, power for lighting, and a communications link to the diving bell. When it snapped, Lemons lost all life support systems except the emergency cylinders strapped to his back.

• umbilical tether
• life support
• heliox
• deep sea diving equipment

A remotely operated vehicle (ROV) located Lemons after roughly 30 minutes underwater. This discovery provided the turning point needed for the rescue team to coordinate his recovery, as his exact location was previously unknown.

Foreshadowing: The documentary establishes early that surface teams had no visual contact with Lemons after the umbilical snapped.

• ROV
• remotely operated vehicle
• underwater rescue
• diver located

David Yuasa, one of Lemons' fellow divers, located him and pulled him back aboard the diving bell. His quick action during the rescue was the critical final step that saved Lemons' life.

• David Yuasa
• diving bell
• rescue diver
• Chris Lemons saved

The minimum time for a proper rescue operation was at least 30 minutes, but Lemons had only 5 minutes of breathable gas remaining. The vessel's drift and the loss of positioning created a critical time gap between when the accident occurred and when help could arrive.

• rescue window
• oxygen supply
• emergency timeline
• survival odds

The dynamic positioning system supplied by Kongsberg Maritime failed while the vessel was operating in rough seas. This caused the Bibby Topaz to lose its fixed position and drift, ultimately dragging the divers away from their worksite and breaking the umbilical.

• Bib Topaz
• dynamic positioning failure
• Kongsberg Maritime
• vessel drift

The divers breathed heliox, a helium-oxygen mixture commonly used in deep-sea commercial diving. Helium is preferred for extreme depths because it reduces the effects of nitrogen narcosis that occurs when breathing regular air under high pressure.

• heliox
• breathing gas
• deep sea diving
• helium oxygen mix

Lemons spent approximately 30 minutes stranded on the seabed at 100 meters depth before being rescued. Remarkably, he survived this duration with only about 5 minutes worth of emergency breathable gas available.

• underwater time
• survival duration
• 30 minutes underwater

The film uses authentic footage and audio recorded at the time of the accident, including helmet cameras worn by the divers and voice communications from their equipment. It also includes interviews with crew members and carefully reconstructed scenes where original footage was unavailable.

• helmet camera
• documentary footage
• voice recordings
• true story