After thinking a little more about it, I am wondering if this particular chain of PS got initiated
when the sound contacted my ears, and my ignorance helped initiate the whole process.
On the other hand, if someone was in deep meditation, that sound would not have initiated the process because that individual would not identify with the sound.
Is my understanding correct that the chain can be initiated from any point, and in my case it started at phassa, and my avijja contributed to the completion of the process, and it ended with the passing away of the sound (the marana/ceasing of this particular PS process) and my next PS got initiated when the next thought got generated in my mind.
Also when one chain of PS is happening, can a another event initiate another PS and overlap this one? In other words, if a person is very agitated does he have a whole bunch of PS happening and multiplying and aiding each other like team effort to make that person extremely agitated which make him/her go in a rage?