Knocking people out is an important part of getting the good ending but what is the point of sparing these people's lives if you take their gas mask filters? They're not going to wake up any time soon so it seems their fate is suffocation. Has anyone else noticed this? Spoiler A similar part of the game is how you can spare Lesnitsky but you just push him aside even though he needs a gas mask to live.
I figure they still have a better chance of surviving with their pulmonary intact, and it's likely either just a minor oversight or something that they deemed not worth the effort to really delve into.
If I remember correctly, you can actually get the good ending and still kill every single enemy you encounter (Maybe with the exception of Letsnitsky and Pavel). Also, I think what is essential in wether or not you kill them with your knife, is your lust for blood or your decision to spare them because you know they're just someone's pawns. Wether or not they survive doesn't matter. What matters is what you, as a person, do to them.