Does he know that the enemy's motivation is so personally focused on Stanley? The remaining person who is most likely to know isn't on speaking terms with the rest of the universe at the moment. Stanley's rant was a hint in that direction, but not a very clear one.
True (except that it would be exactly the same if Stanley had left with a big neon sign saying "THE TITANS' CHOSEN ONE IS HERE" -- Ansom has no units in the area to see him).