Generally, once you get good and benzo'd out, taking more just seems like a good idea so you keep popping them. At the time you remember taking them, it's only in hindsight that you don't remember taking them, you don't remember much of anything. This can be more confusing when its not a total blackout, because you will remember other things that happened before and after taking the other doses, but you generally remember things that were worth remembering, its pretty easy to forget just popping another pill, especially because at the time you probably didn't go back and forth over it debating whether to take it or not you just had the urge and did it, no inhibitions and all.
To prevent this it is best to put your stash somewhere you are not, but if that isn't possible, then you at least need to put as many physical barriers(like inside a cellophane melted shut, put inside a baggie tied tight, stuffed inside of something it will be difficult to get it out of like an empty can, put somewhere out of sight/out of reach like you need to stand on a chair or get down on the ground to get to) between you and them as possible so somewhere along the way you will have to exert enough mental focus to sort of wake yourself up and give yourself pause to decide not to take anymore. Once you cross that threshold if you just got a pocket full of pills chances are you are going to take more than intended.