There was no way Teito would let him get away from him. He needed him, like a fish needs water to live. He needed Frau, as loathe as he was to admit it, and it wasn't just because he'd literally explode if he didn't hear his voice every 48 hours.
But Teito was fragile; his past had seen to that. Killing countless amounts of people, training, killing, losing Mikage… it all led to his current state of mind. The only thing that held Teito together was Frau, or as he fondly thought of him, the perverted bishop.
Meeting Hakuren had helped Teito regain some strength. It was good for him to have a friend other than Mikage, but the thought of losing him almost tore him apart. But Frau was the main reason for Teito's continued life. When Mikage had passed, he thought that he didn't want to live on anymore. But Frau, oh, his beloved Frau, who had no idea of the way that Teito thought about him, had convinced him to stay alive, to live for Mikage. Frau didn't know that he'd made Teito want to live for him as well. Teito had no idea how to tell Frau his feelings, and the idea of rejection weighed heavy on his mind. Teito knew that if he told Frau, and Frau didn't return his feelings he would break.
Or so he thought. Frau watched from afar, unseen by the boy, as Teito sat by the fountain's edge. He had known for a while that Teito had come to depend upon him, and Frau never wanted to break his trust. He never wanted to let go of his charge's hand. But Frau had no way of knowing if some casual action on his behalf might break the boy's spirit, and make him lose hope. The lightest touch might break down all his walls, and he would crumble into dust, like a glass cup dropped on a tiled floor.
In truth, both wanted an anti-shatter future, but neither knew how to begin it.