By doing that, she could begin to use that firmer control over him to demand more from him.
With her being rewarded for each thing she gained out of him and doing what she had been asked to do, it became a whole lot easier for her to keep earning even when she could not take on another task for a while.
Even with her injury, Ash did not miss out on a whole lot, especially when she had always done her best to prepare for such future possibilities where something could have something come up to stop or slow down her original plans.
Most of her preparations could prepare her for what could happen to her, just like her injury, but there were always going to be things that could end up suffering.
She could not account for a sudden task being given to her by Cerberus that could not be refused unless she had a very good reason to refuse.
It was just a matter of whether they would accept her injury as being serious enough to let her avoid having to take on such a task.
