beware of open windows

In the Irving's Hotel New Hampshire I was reading in high school long long time ago is a famous sentence translated in Finnish as above. I got the suicidal context, but found it a bit weird, as one might rather use it in opposite meaning, not to leave passway for the dangers from outside. Today I learned the original expression is Keep passing the open windows. I feel decieved and think I need to read the whole book again, in English.