Work began on preparing the site for the Ambassador's foundations when tragedy struck on the morning of Saturday, 22nd October 1927. Two workers, John Gannon (31) of 36 Jennings Street, Salford, and John Gregg (31) of 10 Chapel Street, Pendleton, tragically lost their lives. John Gannon was a steadfast labourer, known among his mates for his quiet reliability. John Gregg, similarly devoted to his craft, had married Mary Somers in April 1923 at Barton Upon Irwell, Lancashire—a quiet union that spoke to the simple joys of life in the industrial heartlands. The couple had no children, leaving Mary to face unimaginable grief in the years ahead.

The site had previously been an old cinder tip, and although this was known to Gerrard and Sons Ltd., of Swinton, who had been contracted to prepare the site for building, there was a lack of awareness about the dangers posed to their workers when digging the shafts. 

The men were sinking a shaft as a preliminary to laying the foundations for the new cinema. It is believed that gases had collected at the bottom of the 25ft shaft during the excavation over the previous fortnight. 

An eyewitness described the rescue to a reporter at the time: 

    “Men came running from all directions and peered into the mouth of the shaft. A man tied a running noose in the windlass rope and let it down into the pit. He drew it gently over the head and shoulders of Gregg, who was on top of Gannon. We all pulled at the rope. We were surprised to find that both men came to the surface. That was because Gregg’s arms were tightly wound around Gannon’s body. Gregg’s last thought, presumably, had been to clasp Gannon and raise him. We had the greatest difficulty in unclasping Gregg’s arms.”

Another witness, Joe Barrick of Earl Street, Swinton, added:          “I saw the rope from the winch dangling within a foot or two of the men in the shaft. The man underneath lay flat on his face and was absolutely still, and Gregg lay on top of him, grasping his clothing. He was badly gassed, and as I looked, he relaxed and lay still."

Despite attempts at resuscitation by Wadsworth and PC Harry Spencer, both men sadly died at the scene. At the Coroner’s inquest, Edward Wadsworth said that without hesitation, Gregg had gone immediately to Gannon's assistance but collapsed when some feet from the bottom. "I ran to inform the Police," he said, "and after the assistance of pedestrians had been enlisted, the men were hauled to the surface. It was a great shock to me, and I cannot speak too highly of Gregg’s courage and self-sacrifice."

Recent information from the Carnegie Hero Fund Trust clarifies that John Gannon's legs became entangled in the rope during his collapse, rather than being deliberately attached or tied to it. This detail explains why pulling him up directly was not attempted and underscores the necessity of Gregg's brave descent into the shaft. In a final, desperate act of brotherhood, Gregg clasped Gannon tightly in his arms before succumbing himself—his grip so unyielding that rescuers later struggled to pry them apart. 

The coroner praised Gregg's selfless heroism, stating, "Greater nobility of mind and heart could no man show than did John Gregg, who, regardless of the risk he was running, bravely descended the shaft in which his colleague was lying in a helpless condition, with the heroic object of recovering him, and himself fell a victim to the presence of gas. These men lost their lives by being asphyxiated in a shaft, twenty-five feet deep. They lost their lives in a manner that cannot fail to call forth the deepest expressions of sympathy and regret, and also, in regard to one of the victims, great admiration. " 

The coroner added, " There may be a matter to consider whether the employer took reasonable precautions for the safety of the men."

Mary Gregg, John Gregg's widow, provided crucial insight during the inquest. She revealed that her husband had felt drowsy the night before the incident, suspecting it was due to the foul air in the shaft. She said, "He thought the drowsiness was due to the bad air in the shaft."  

Wadsworth, who went to report the accident to the police, said they did not try to pull Gannon up despite the rope entanglement. The Coroner suggested, “You might have brought him up.” to which Wadsworth replied, “It was just the thought of the moment.“  

Police Constable Harry Spencer, who had applied artificial respiration, was commended by the Coroner for the admirable promptitude which he had shown.

Wadsworth, said Mr Richardson, the manager, had been to inspect the workings the day before. Mr. Richardson, a director of Gerrard and Sons, stated that there had never been any complaint about foul air or smell.   He recalled that an employee had once told him that they had to "bat the air," but Richardson believed this simply meant it was warm.

The Coroner pressed further, stating, “I suppose you now realise the danger which exists in excavating in a confined place?” to which Mr Richardson replied, “I do realise this danger, but I have never come across it previously.”   He knew the site was an old cinder tip. The Coroner asked, “Do you know foul gases do accumulate in these pits? "  Mr. Richardson replied, “I believe so, but I have never known anybody to be overcome.”   The Coroner continued, “There are no appliances for use in the case of foul air?” Mr Richardson stated, “We had none on the job. "   The coroner then asked, ” Are any tests ever made?” to which Mr Richardson replied, “Not in this case.”   The coroner queried, ” Have you known any tests in other cases?” to which Mr Richardson said he did not.