A trolleybus had lost control and had fallen into a reservoir. It was 25 meters (82 ft) off-shore and had sunk to a depth of 10 meters (33 ft). Karapetyan immediately dived into the sewage-infested waters and managed to kick the back window of the trolleybus with his legs, despite zero visibility from the silt that had risen from the bottom. Of the 92 passengers onboard, Karapetyan pulled out 46 people. 20 of whom survived. The combination of cold water and the multiple lacerations from glass shards led him to be hospitalized for 45 days. He developed pneumonia and sepsis. While he was able to recover, damage to his lungs prevented him from continuing his career as a swimmer.