ananome,
you don't have to be a violent or hurtful person to have suicidal thoughts. Sometimes there are triggers that we may not be aware of at the time. Smells, sounds, music, dreams. All can trigger unwanted thoughts.

I do believe that your thoughts are involuntary. They are probably unnerving as well. I'm new, so I don't know your background as well as others on this forum, but I am aquainted with thoughts like that.

The other day I was driving my car and had a strong urge to turn the car into a tree. Nothing preceeded the thought as far as I know, but it too was involuntary. I'm sorry you have had to have even three of those moments. Sometimes I wonder if more people have such thoughts than would admit to it. Talking about it to others here that understand may help you figure out why that has happened to you.

Sam2