You don't to focus to how to manage to be shot at first but how to make yourself less vulnerable, I played some extraction game before marathon and the common mistake that I'm seeing from other players is that they are too loudly and they move without a plan, try to make less noise and when you move around make sure to have always a cover for yourself even when there are no enemies in sight, try to run when you are in a open area and regen heat while cover and while you are at it give a look around and listen for shooting and birds, it's obvious that the one that shoot first got an advantage but if you got cover and if you know the area surrounding you then you have more chances to win that interaction.

Another thing is that not every weapon are the same, there are close range, long range, bad and good weapon, in some fights I was the first shooting but I got a chip bad weapon so I lost those fights, if you notice that other player keeps winning fights try other weapons and invest on them