His first mistake came when he decided to get in his car while having a blood alcohol level of 2.8 - that is, the equivalent of around nine beers.
The drunk copper then smashed into another car on the Autobahn, causing a whole section of the road to be shut down, Bild reports.
Officers who turned up at the scene breathalyzed their colleague and found him way over the limit.
In order to have a blood-alcohol level test that could be used in court, the officers took the drunk copper to the station where a doctor was supposed to take a blood sample.
But before the test could be done, the inebriated policeman pleaded to be allowed to go to the loo.
Out of sight of his colleagues, the cop clambered out the toilet window and jumped onto a roof below.
But he was out of luck. His landing spot was eight metres below and he sustained a broken arm as well as a fractured his pelvis and severe bruising.
Police who retrieved him took him to hospital.
The officers who brought him in are now threatened with a disciplinary process.
They appear to have failed in their duty of supervision, from the point of taking him into custody until his escape, an investigator told Bild.