Cutscene skip: before 47's left fist appears in the frame. The guard at the exposition can see you through that wall, but he always turns his head right, so you can slide past him and avoid camera. This can be turned into consistent 1:40+ with: -latest cutscene -waiting for the guard to pass; -getting spotted by the camera and having to erase the recording later; -a bit slower propane kill because security room guard gets alerted while he's outside.