I think it's quite normal.

If someone is struggling with suicidality, it isn't just one fleeting thought, it remains in the mind and continues to "play out in the mind" until there's a resolution, which, hopefully would be a lift of depression and the suicidality dissipates.

The suicidal thoughts can be very intrusive, meaning the can occur without first consciously pondering them.

Please be safe.

WC