The buttons are mid way up the wall and there is no visible redstone, which adds to the sexiness factor.
All the redstone is nicely concealed and it's fairly neat, this method is pretty useful and has a lot of external applications! Hope you find it useful!!
Not only this, the door is untamperable, which means you have to use the combination lock. I go into a little bit of detail on how it works on the video, but essentially I get some of my design from CNB Minecrafts combination lock design and made it my own.