I discovered while mining in a 1 block high tunnel/strip mine that if you save and exit while in a 1 high tunnel, when you load back into the world it spawns you at closest 2 high spot above where you were. I originally done this on accident in the Mesa biome mining 1 particular colour using the swimming ability to swim into the 1 block high gap. I also noticed while in a one block high mine that hostile mobs dont seem to attack you unless you attack first? These only include spiders and baby zombies as they fit in a 1 high block.