Policy may be stupid, but it is the policy.
If the policy requires the gun to be off person and secured during flight, why was he trying to remove his gun, while preparing for landing. Seems to me that getting the plane prepared for landing and landing it are the most important things to do.
Based on the small amount of information available (a dangerous way to draw conclusions), that tells me the pilot chooses not to follow a policy that he thinks is not appropriate, or that he knows better then the policy. In this on case that may be true, but it shows a willingness to make those decisions on his own in a nonemergency sitsuation. A poor showing of operational discipline.
I do think they should NOT have a round chambered. I understand the concept of a chambered round in a law enforcement or personnel protection type scenario. But the fact is in the cockpit he will not be able to quick draw this weapon, and should not be in a sitsuation where he has to anyways because of the cockpit door. In that scenario, the safety provided to the passengers, plane, other pilot, and the gun toting pilot, out weigh the advantages and would say no round chambered. It only takes about a tenth of a second to chamber a round for a person who is proficient in the use of his firearm (again, only people who are proficient should be carrying, especially in a plane)