I ran across this version of events which is again slightly different. This is from the US Maritime Administration:
https://www.maritime.dot.gov/history...thaniel-greene
What is interesting here is what is said about the man who was washed overboard from the Greene.
" Two Armed Guard gunners and five merchant crewmen were injured.
An additional crewman was washed overboard, although he was recovered alive. "
So perhaps the Scylla did pick up a Messman who was alive. The witness just confused which ship the Messman was from.