How was Duncan able to predict the exact moment a silenced sniper rifle would be fired?

In the movie Polar that stars Mads Mikkelsen, Duncan, his character and an assassin, was being hunted down by the same organization he used to work so they wouldn't have to pay his 'pension' on his retirement.

During a scene where one of the hunters from the organization had sex with him in order to catch him off-guard and kill him easily, he was able to:

• predict the exact moment the gunshot, from a sniper which was silenced, was fired
• pushed the woman he was having sex with so she was shot instead
• was able to kill all of the hunters except one

I would understand if he was suspicious of the woman who had sex with him. But how was he able to go so far as predict the exact time the sniper was shot and push the woman so she would be hit instead? Is this even possible? As far as I know, the film is not about people with powers similar to superheroes. Furthermore, while the laser sight was aimed at him, his back was facing towards the sniper, so there was no way to see it.

Here's a video of it.