Mental stability test by doctor

In a “Mental Hospital” a Journalist asks the Doctor :

” How do You determine whether to admit a Mental Patient or Not…?”
Dr : Well…. we’d fill a Bathtub with Water and then give

1) a  Teaspoon,
2) a Glass &
3) a Bucket
to the Patient and ask them to empty the Bathtub.
Journalist : Oh, obviously a normal person would use the Bucket  because its Bigger.
Dr : ” No, a normal Person would pull the Drain plug….

You, Please go to Bed No.39.

We will start further Investigations on You…!”