Found a way to clip through the door in purgatory after you pick up the notebook. I've only gotten it to save around 5 seconds, but I think if done optimally it could save around 10. (Edit: Did a test run and found that this can save up to 15 seconds.)

Had this happen in a run. I had it happen before but wasn't recording. Don't know how it works but it saves around 5 seconds.