### "Look closely. Closer... I'm in plain sight, yet you are not looking. Lightning flashes." ###
>! Using the "look closely" hint, I finally got somewhere. If you look closely at the image of the lobby, in the upper left corner the number 72315 briefly appears.  <br/><br/>
>! [![72315][1]][1]
>! [![image][2]][2]   


  [1]: https://i.sstatic.net/uFb5m.png
  [2]: https://i.sstatic.net/gu1FV.gif