That reality check works just not for you at that momment, why??? cant say. I have had experiences also where something worked one time in a lucid but doesn't work the next time. Just look at it as a opportunity to experiment with other reality checks. With lucid dreaming there is no "A" your here "B" your there you just have to adjust to whats happening around you. thats why its a gd idea to soak up as much information about lucid dreaming as you can and ap info is also gd for ld's. namaste.