Sounds like The Quiet Earth, NZ 1985.
Zac Hobson wakes up to find that he is apparently the only person left on Earth. Soon, however, he meets others - Joanne, a pretty young woman, and Api, a huge Maori tribesman. They survived the apocalypse (a malfunction of a government project in which Zac was involved) because all three were at the moment of death--Zac's attempted suicide, Joanne's exploding hair dryer, Api fighting with another man--when the apocalypse occurred. Soon, however, Zac and Api begin fighting over Joanne, and the trouble begins
IMDB ... Written by Anonymous
He enters his underground laboratory; a monitor displays the message "Project Flashlight Complete". The mass disappearance seems to coincide with the moment Flashlight was activated. He notes on his tape recorder:
"Zac Hobson, July 5th. One: there has been a malfunction in Project Flashlight with devastating results. Two: it seems I am the only person left on Earth."
at the instant of The Effect, they were all at the moment of death—Api was being drowned in a fight, Joanne was electrocuted by a faulty hairdryer, and Zac had overdosed on pills in a suicide attempt. He had realized there were serious dangers with the experiment and was guilt-ridden for not speaking out.
There is also a Youtube-Version of the film. The scene you remember is starting at minute 56:55