The last line's a pun.
People might say that "death" and "Death" are not a real pun and that it's a lame pun at best, but to me it's a very real pun.
Because to "wait for Death" to me signifies either begging for death or angrily challenging Death for continued life.
Whereas to "wait for death" to me signifies giving up and awaiting death. Neither trying for it nor avoid it, merely being passive.
So the pun (here) encompasses the begging of the first (Death) as well as the second (death).
The poem's on Katie. I had said bad things about Lois-Ann Yamanaka in my LJ and felt like crying because I knew that made me less perfect for her. I figured she'd... like me less the next day and that I'd then want suicide (or to wait for death). As it was, Katie... was nice to say the least and said she wasn't mad or upset though she disagreed w/ my view of Lois-Ann Yamanaka.