This Is Gospel Panic! at the Disco

I think it is about how Spencer was bottling up everything about his addiction, to the point where he was falling apart. However the reason he was bottling it up was also, ultimately, so he wouldn't look as though he had fallen apart in front of the people he loves and who cares about him.

The scene with the doctors links with the whole part of prescription drugs and what he was taking. Almost as if the Doctors were holding him back from getting the drugs, but in the end, they gave up and prescribed them (when Brendon was sedated). 

The scene with the coffin could also be to suggest he knew his fate if he continued, but also that because of him bottling his emotions and secrets up, he was drowning. And the fact that Brendon was still wearing his converse highlights that he was comfortable in that outfit; they are casual. Demonstrating that Spencer felt comfortable knowing nobody knew about his secret even if it was tearing him apart from the inside out.

Then the scene with the splashing water and ropes can demonstrate his 'coming to terms' with his problems and trying to break free. The ropes could be a personification of himself trying to hold him back; to get back to the comfort of the secret and the drugs locked away inside of him 'till death do us part' (the coffin). However he managed to break free, therefore portraying his decision to receive help and announce it to fans.