i believe there's definately more to this..... hopefully they come out with a full investigation and report.
normally, if you flick the switch and open the cockpit door, after a while.. if the other crew member doesn't come in, would you keep holding it? or let it go? i would let it go and check the camera to see what is he doing.
i don't know bout the 737s... i fly the A320.. and when i flick the open door switch, i'll hear a loud "Tack" indicating that the door strikers are unlocked.