"Oh, and by the way, who was supposed to have witnessed that trial and made a transcript?"
I noticed these details as I was reading about Jesus' trial in Mark:
"Peter followed him [Jesus] at a distance, right into the courtyard of the high priest. There he sat with the guards and warmed himself at the fire" (14:54).
"While Peter was below in the courtyard" (14:66).
I don't know if this means that Peter could see or hear the trial, but I took it that way initially and thought it was a nice touch (artistically speaking) and it appears to be taken this way in commentaries as well:
"The place where Jesus stood before the high priest may have been an open room, or place of audience on the ground floor, in the rear or on one side of the court; such rooms, open in front, being customary. It was close upon the court, for Jesus heard all that was going on around the fire, and turned and looked upon Peter (Lu 22:61)."
"At the upper end of this court, probably, would be the memorable chamber in which the trial was held—open to the court, likely, and not far from the fire (as we gather from Lu 22:61), but on a higher level; for (as our verse says) the court, with Peter in it, was "beneath" it. The ascent to the Council chamber was perhaps by a short flight of steps."
And the first thing that came to my mind when I saw these verses was Papias' statement that Mark got his information from Peter:
"Mark having become the interpreter of Peter, wrote down accurately whatsoever he remembered. It was not, however, in exact order that he related the sayings or deeds of Christ. For he neither heard the Lord nor accompanied Him. But afterwards, as I said, he accompanied Peter, who accommodated his instructions to the necessities [of his hearers], but with no intention of giving a regular narrative of the Lord's sayings."
But I don't know if these verses had anything to do with this tradition.
Show me something built to last.