• Blue Arrow: Run and Jump
  
• Green Circle: Vault position
  
• Red Arrow: Run and vault

Instead of using the ladder to climb to the roof use this vault, this will make less sound and won't make you as vulnerable as if you were climbing the ladder. The vault is also further from the window inside meaning that you have a higher chance of surviving a shotgun shot while getting to the roof.

This is a consistent Beetle spawn location at Lockbay Docks, located on the NE side of Lockbay on the big tree.