Here's a description of the JetBlue incident from the LA Times:
Osbon [the captain] began speaking incoherently and became increasingly agitated as the flight went on.
After yelling at air traffic controllers, he turned off the radios in the Airbus 320, which had more than 130 people on board, and "sternly admonished the FO for trying to talk on the radio."
"The FO became really worried when Osbon said, 'We need to take a leap of faith,' " investigators said.
Initial reports after the jet made an emergency landing in Amarillo, Texas, said the co-pilot had tricked Osbon into leaving the cockpit by suggesting he use the bathroom. The complaint says Osbon bolted out of the cockpit on his own and headed for the bathroom, alarming crew members. This was about 3 1/2 hours into the five-hour flight.
In the ensuing melee, Osbon reportedly "aggressively grabbed" a flight attendant's hands; banged on the bathroom door and yelled at a woman inside to get out; yelled at passengers; and pounded so hard on the locked cockpit door that the first officer feared Osbon was breaking through the bulletproof barrier.
I don't think anybody on either side of the door was ever in any doubt about which pilot was the sane one.