In the early hours of October 10, 2011, the day of the killing, police were called when she told cab office employees that she needed to be sectioned.She was taken to the Queen Elizabeth Hospital where officers helped her book in at reception at around 4.30am.
But as they left, Edgington told them she did not feel safe there. She made a series of phone calls and later 999 calls.
In one call, she said: "I'm a very dangerous schizophrenic. If you don't come and help me I'm going end up hurting someone."
Edgington was accepted to the hospital's onsite psychiatric unit Oxleas House, but was not taken there until 6.30am.
But just after 7am, Edgington said she was going to call her care co-ordinator and left. Staff called police.
Edgington calmly took two buses to Bexleyheath, south east London, and bought a large knife from an Asda supermarket, before she attacked her two victims.