To break a promise one has made.

Watching intently (from a vantage point, for someone or something).

(idiomatic, possibly somewhat dated, informal) To do what one considers to be best suited or most satisfying for oneself; to do what expresses one's distinctive interests or talents; to do as one chooses.

Alternative form of until one's dying day

(literary) At the point when one about to die.

Alternative form of with one's last breath

To commit suicide. / To spend the rest of one's life a certain way.

To spend the rest of one's life in a certain way.

To engage in mental activity without being distracted by noise.

As long as one lives.