Shane was awaiting his boys return. He has been trying to get through to them to no avail. He started developing a bad feeling about it.
He has been trying to not go into a war with Nathan's men because, even though they appear simple on the outside; they shouldn't be toy with. He hadn't gotten a taste of their power before, but has heard of those who do. Which is why he tried to find out their source of power when he get this feeling that he has somehow gotten on the current leader bad side.
He lost his sense of reasoning and sent out his men after them because Nathan interfered with something he would never let go even if his life is put on the line, 'his wife.'
