First, confirm that you're on the most current version of the game, 1.0.5. This was an issue that was fixed previously (though it's possible there's more to fix). Version number can be found either in the folder name or the readme.txt in the www folder.
If you ARE using the most recent version, please describe the exact sequence you're using to reproduce the bug in question. You're loading the sewer scene from the gallery, quitting out via the locker (at what point? after going how far through the scene?), and then immediately starting the scene again from the gallery and encountering scene overlap/things triggering when they shouldn't (at what point?). Doing some basic poking around I wasn't able to reproduce, but I'll try again once I have further details.