at some point in game before the Mill door 5 slaves wandering/going back and foreward(in corner next to a truck)and also some1 is whiste,i cant get any reaction or anything,so is there something to this?

Person Whistling or a Steam Whistle? I think there are both in the Pitt area. There are lots of sounds in the game that are just purely background and atmosphere have nothing to do with the tasks at hand. This is why you hear gun shots out in the wasteland and can't find anyone shooting. Although I think the gun shot sounds are a bug as there are a couple of mods that remove those.

So, this is probably nothing but atmosphere.