Interesting how all the supposition so far has the righteous F/O standing up to the dastardly Captain who wants to throw the SOPs out the window.
That's not a million miles away from what one (supposed) passenger is claiming:
Pilot was coming in 10 knots faster then he should have been [on arrival into Lubbock], co-pilot then radioed tower and told them, which started argument in cockpit as they landed.
Co-pilot and pilot [disembarked], we all boarded and were seated. The fight attendant proceeded with her preparation, she then announced that due to a disagreement between pilot and copilot she felt it was unsafe to fly with them, she felt our captain was unstable as did our copilot and for our protection we needed to disembark.
As I was going up the jet way [to get off the plane] our captain comes running down the jet way yelling “who told us to get off.” I was out of jet way but I could her him yelling at our flight attendant, we all waited by ticket agent stand as the last customer came out the door was closed, and 5 minutes later police arrived.
Flight attendant and co-pilot were afraid captain would do something that would put us in danger and they took a stand. We all thanked our flight attendant and the co-pilot for looking out for us.
What Actually Happened On That United Express Flight Where the Fight Broke Out Between Pilot and Co-Pilot - View from the Wing