Suicide
Suicide is the act of killing oneself.
About
Genesis
Peter Petrelli has a recurring vision of what appears to be a suicide attempt. He dreams himself falling/flying off the top of a tall New York building.
Claire Bennet, in an apparent suicide attempt, jumps off an 80-foot platform, caught on tape by Zach. She also mentions that she has stabbed herself in the chest and shoved a steel rod through her neck, all in an attempt to seriously hurt herself or prove her power of regeneration.
Don't Look Back
Nathan tries to explain the fact that he and Peter flew as a failed suicide attempt by Peter. Much later that night, Nathan watches as Peter threatens to jump off the edge of the roof unless Nathan admits that he flew.
One Giant Leap
In a press conference aimed at helping his campaign, Nathan (falsely) claims that Peter attempted suicide.
Collision
Confident of her regenerative powers, and intent on teaching Brody Mitchum a lesson, Claire purposely crashes her car into a wall in what would appear to most to be a suicide. (According to Aftermath, Claire was not wearing a seatbelt.)
Homecoming
Unsure what will happen to him, Peter jumps off the roof of Union Wells High School. He subsequently mimics Claire's power of regeneration, and is healed.
Fallout
At the Odessa Police Department, Peter tells Claire that this healing power is new to him and that he didn't know he was going to be alright when he jumped off the building with Sylar.