I've been playing through Metro 2033 again to try and get the super happy ending where everyone can be friends and dance the night away. I think I got a decent amount of moral good things, but when I got to the library I began going through gas masks really quickly for no reason, meaning I died of not breathing, meaning I had to reload at Polis and lose all of my loveliness points. Is all of the asphyxiation supposed to happen, or is there a glitch?