English Translation
The burglars appear to have been surprised by the watchman.
This sentence is currently translated as “watchman” which, although correct, is a bit less common than the word “guard” or “security guard”, especially in contemporary times. Also, I think because “watchman” sounds more similar to “Wachmann” (even if it is not a direct cognate, i.e. watch is not the same as “wach”=awake/alert) changing this to “guard” might improve the teaching value of this sentence, making people do more work to recall the word based on its meaning rather than based on a convenient coincidence of sounds.