Thank you for your comments & suggestions. I agree with you, the two occupations seem irreconcilable & at present, I am grasping at the fact that men conscripted to war can train & take up occupations different to their peacetime occupations. The 10 years between Census returns is a long time & he could have trained as an Army Surgeon in that time.
I thought that he might have been engaged in the Crimean War effort where many men lost their lives. I am not sure if there were any other wars in that period he might have been engaged in.
Thank you for your suggestions. You have given me a new area in which to research.