Lower your defense, lower your casket.
Well, it says that mediocrity is the killer, so if you lower you defense and become mediocre (in life in general), you are soon to die.
Doing the waltz with your murderer means that you enjoy being mediocre.
The song takes a change of pace and continues on about a relationship.
I believe that the first and second part of the song is completely irrelevant to each other, but it's just how I perceive the song.
You all are clearly reading too much into it.
Lower your defense, lower your casket. Well, it says that mediocrity is the killer, so if you lower you defense and become mediocre (in life in general), you are soon to die. Doing the waltz with your murderer means that you enjoy being mediocre.
The song takes a change of pace and continues on about a relationship. I believe that the first and second part of the song is completely irrelevant to each other, but it's just how I perceive the song.