Lyric discussion by thexauthor 

Cover art for Planning A Prison Break lyrics by Receiving End Of Sirens, The

So I was confused about this song until I read this: "If anything I would say I live by the standards I set for myself and strive to obtain them daily. This is where the lyric "This is the last night in my body." comes from. It was and is about being unsatisfied with how I am living and vowing to my self to never just settle or accept the way I am living."

That was in an interview and Brendan's answer to what was his life motto. So I guess this song is about getting out of old habits, and changing into who you want to be, I can't put it in any better words than what Brendan said himself.