Actually I've read Bruce Lee's books, and he advises people to avoid any fight if they don't have a good chance of winning.
My own Shifu (martial arts teacher) has won multiple Kung Fu Championships here, and he also has the same advice. Back out unless you have a very high probability of winning.
Even the best can't win if they are too outnumbered. In this Germany situation for example, the attackers had all the advantages. Numbers, the element of surprise, weapons, etc. In this situation you simply have to escape. Or avoid it in the first place.
If you are fighting more than 1 opponent you will always be at a severe disadvantage. And unfortunately these as$holes usually attack in packs, if they were honorable enough to go 1v1 then they wouldn't be as$holes in the first place.