Complex sentence: During a later encounter in the hospital, he told Mary that he would write a book about her and give her all the royalties; she angrily rejected his proposal and locked herself in the bathroom until he left.
Split into simpler sentences: During a later encounter when Mary was hospitalised, he told her that he would write a book about her and give her all the royalties. She angrily rejected his proposal and locked herself in the bathroom until he left.