Let's say I am staing at a hostel and there is only one electric kettle. I need to to boil some water to cook a meal. So I take it fill it up and turn it on. To cook a meal I need all the water. It boils, but then another person comes up and take the kettle not knowing that I am the person who filled it up and that I need all the water. So does the use of occupy sound natural in the following sentence?
I am sorry, but I occupied the kettle first.
I am almost sure that the sentence doesn't sound natural, but I have no clue what a native English speaker would say to communicate the meaning.