You're gonna die!

I said that. To a woman who was biking in the middle of the street, at dusk, without any light on her or her bike, no helmet. I don't know if she realized that she was completely invisible to any car coming behind her.
I was coming back from Home Depot. This, in itself, is a small miracle. I could live there. Stay and explore for hours and hours. Each aisle is calling me for a project never finished, sometimes never started. Each idea is like a dream of what I could do, a succession of promises that I can't never keep.
I saw her at the last minute. A car was coming toward mine and I saw it changing direction without any apparent reason. That's when I realize that something or someone was there that had forced that car to swerve. The same way astronomers discover black holes: watching the effect they have on their environment, even if they remain hidden.
I flashed my high beam lights a couple of times and finally saw her. A small dark figure zigzagging from left to right on the road, in the dark. Completely invisible. Suicidal.
I should have known better though than trying to explain to her that what she was doing was so dangerous. I stopped my car in front of her, trying without success to lower the window of the front passenger side. I mixed the buttons and the rear window goes down instead. "Do you realize how dangerous is what you are doing?" I admonish her, feeling good to be doing her a favor. She looks at me as if I was wearing the orange suit of a psychiatric hospital. "Well, you are the one who is a menace. You stopped right in front of me without warning." She gets back on her bike and crossing from right to left in front of my car, she disappears in the nearby back alley. I just have the time to shout "Don't you understand? You're gonna die!!"
The sentence does not sound exactly like what I should have said. The words just came out this way. It feels more like a curse than like a warning.