> the bankers realized that Morgan had locked them in the library and pocketed the key to force a solution, the sort of strong-arm tactic he had been known to use in the past.

While that story is often repeated it sounds for sure apocryphal. A bunch of men from that day and age couldn't have figured out how to get out of that room? Or simply revolted and freaked out? Now maybe he feigned doing that or maybe he actually did 'lock the door' but so what? The story and legend value is just to much to ignore. It's almost certainly greatly exaggerated or not even close to being true. People can't even agree on news that happened in this day and age let alone the golden era of back in the day newspaper exaggeration.

In any case the 'lock' might have been some other leverage he used over the players that wouldn't make sense to the general public or make a good news story.