But would there be daylight outside? Perhaps there was a street light that helped light up the basement. Are we sure there was no light in the basement?
We don't actually know what the lighting set up was in the basement.
I was just thinking out loud when I started talking about the basement lighting.
B has allegedly said that he thought that perhaps he'd accidentally left the shutters open in the basement.
This made me think several things.
Firstly, why not say 'one of us may have left the shutters open'?
Secondly, given the weight of what had happened that night, and the important role the shutters played, if this was me, I think I'd realise it was I who had made the fatal error of leaving them open, unless I frequently opened and sometimes forgot to close them, in which case, I'd have no idea. For example, I frequently don't lock the doors to my roof terrace because the cat is constantly wanting to come in, then go out, then come in again.... and I'm not on the ground floor, so I'm not too concerned.
SO, if he can't remember whether he left them open, this suggests to me that a) he's the only one who opens them and b) it's not rare for him to do so. So why does he open and (sometimes) close them? Is it that there's no light in the basement and he needs to open the shutters to let some light in so he can see what he's doing? (like hiding money in the Monopoly box, for example).
But it sounds like it would have been dark in the basement when the robbers struck and they managed to locate the money, so it does sound like there was a light in there.
And that leaves me with the question, why does B open the shutters at all?
But then there was another report somewhere that suggested that the shutters were faulty.
So I give up.