Any scientific reason why the safe light pointing at the window won't work? There would be minimal light coming in from the windows at night but I will have to cover the walk out basement door.
The light coming from the safe light won't interact in any (measurable, real life, not quantum physics) way with any light coming in from the windows.
So the questions to be asked really are:
1) will the light from the windows create a problem? and
2) is it a good idea to point a safelight at a window?
The answer to the first question is: probably - the existing light at night may be enough to cause problems, and if not all it takes is for a car's headlights to hit the window for there to be a real chance of fogging.
The answer to the second question is no, because it will just waste the safe light. It is usually best to point a safelight at a larger, semi-reflective light surface like a ceiling, in order to maximize the benefit of the safe light and to increase the effective distance between the safelight and the paper.