We know Captain John Rippey was in the Pennsylvania militia in the Revolution. But what did he do? I've never seen evidence of his participating in any battles. I think, though I'm relying on an increasingly unreliable memory, I saw some mention in the Pennsylvania archives of his possibly acting as a supply officer. (An unglamorous job, but someone has to do it. )
There's another possibility, maybe even more unglamorous but equally essential.
See this post at Universal York for very good background on the prison camp in the York. The York militia definitely were guards for the camp, but no specific mention of one John Rippey.