Why did she do it???

Within the last month, this bit was in our paper:  “Authorities say a 30-year-old woman from Everett died after she drove her Jeep Cherokee through a barrier and off a dock at the Washington State Ferries terminal at Anacortes.  A preliminary investigation found that Nicole Barney arrived at the ferry about 7:50 am, paid the ferry fare, then drove into the vehicle parking area. About 9:45 she drove off quickly and went off the end of the dock.”

Poor, poor dear soul. So sorry for her family. Why did she do it?