Something that's been Confusing me since Childhood

I would like you to watch the above video and share your opinion on what on earth is going on here...I have no idea.

It seems like there is a weird Scottish man who wants to find a room to shriek out of and eventually he does but, strangely, it's a room on the bottom floor and his voice wouldn't carry as far as if he'd chosen a top room.  Why does he have to switch all the lights on and off even though it is quite clearly daytime? Why are the curtains drawn anyway? And if this is house number 4, where are numbers 1, 2 and 3? Seriously, any help on this one would be greatly appreciated.

Thanks.