My mom was dying of cancer, and was in a medically induced coma due to a downturn in her health after a hospital transfer. My dad and two sisters were there, and her older sister had flown across the country in order to see her before she passed.  My aunt had just gotten to the hospital, got to talk with her for a few minutes on her own, and we all went back in after.  We were in the room for maybe another ten minutes when she coded and they couldn't bring her back.

We believe she waited for her older sister who she hadn't been able to see in years to get there, and she was one of the people in her family (besides her dad that had passed five or six years previously) that hadn't been terrible to her when she grew up.  Once she arrived it must have felt like the right time to go.