I see a lot of my younger self in you. I was a single parent when my daughter turned 1 until I met my husband not long after her 4th birthday, and those days were tough, and the worst days of my life. Please remember she is still only little. Asking her if she wants to die, will put the fear of God her, and she honestly doesn’t need to be hearing it so young. Even if it works and she doesn’t do it again
I also have a runner, especially when we went on holiday, and I had to be diplomatic and just say ‘we don’t run away, you need to stay with mummy and daddy’ he doesn’t need to know he may be kidnapped and never see us again.
I’ve also started to change the way I talk to him, and stopped saying naughty (I’m awful for it). He’s number 3, and I’m still learning what works and doesn’t for each of these kids