Let's say I started a kettle and it has just reached a boiling point. And then my friend comes up to the kettle, not knowing it has just boiled the water, to turn it on. What the most natural way to say that the water has just reached a boiling? Which of the following sentences sound the most natural?
It just boiled.
I just boiled up.
It just went off.
It just turn off.
I would like to know American and British ways to say it.