"I'm not concerned about all hell breaking loose, but that a PART of hell will break loose... it'll be much harder to detect"

George Carlin's quote is a cautioning about the risks of complacency. He is suggesting that it is insufficient to simply understand the capacity for catastrophe, but that we should be alert in order to prevent it. He is stating that if just a part of hell break out, it will be much harder to identify and for that reason much more difficult to avoid. This is since the effects of a partial disaster might be more subtle and insidious than those of a full-blown disaster. Carlin is warning us to be aware of the potential for disaster and to take steps to avoid it, rather than simply assuming that all will be well. He is highlighting the value of being proactive in order to protect ourselves and our neighborhoods from damage.