From what Ive read and heard over the years the impression I got was Munzer wouldn't listen to anyone who told him to slow down and dial it back. People who talked with him about what he took, how much and why, were surprised at how little he knew about the pharmacology of it.
When you are already known as the most ripped bodybuilder ever and year after year you put on more and more size but you're still placing in the bottom of the top 10 its time to find a different sport, but he just continuously upped the dose until he was maxed out year around.
Internal organs and bodily systems (nervous system, circulatory system, respiratory system etc...) work together. When any begin to fail, the others compensate by working harder- which then taxes those systems/organs as well. When one fails its only a matter of time before the others fail too. At some point, he was a dead man walking.