Purely a hunch on my part, hence the preface “I’m of the mind...”. It wasn’t presented as fact supported by evidence, so your request for said evidence is somewhat puzzling.
(1) Mr. Lakin made the rank of Lt. Colonel. Such AWOL behavior or proclivity is exceedingly rare in such a rank, from what I understand of human nature and anecdotal personal experience. It's like a major league pitcher refusing to take the mound for stage fright.
(2) Doctor Lakin was Chief of Primary Care and Flight Surgeon charged with caring for Army Chief of Staff General Casey’s pilots and air crew. Would General Casey have allowed a slacker or coward such an important high-level duty?
(3) Colonel Lakin served 18 consecutive years in the military. A person doesn't throw away a lifetime career for silly fears.
(4) Colonel Lakin has served overseas many times: Honduras, Bosnia, El Salvador, Korea and Afghanistan. The Bosnia and Afghanistan service would be, I think, war zone service. Not a man unable to travel, and with war-zone experience.
(5) Colonel Lakin won many decorations including, among many others, the Army Flight Surgeon Badge, and the Combat Medical Badge. Not a slacker.
So I ask you -- on what basis do you make such a slanderous claim?