Woody Van Dyke on leave from service?!

the comments and trivia about the movie say that woody van dyke, the director, was brought in after he was given two weeks leave from the military service.

this movie was completed and released in march of 1941.

since van dyke was a director of the first rank in hollywood, this begs the question: what was w s van dyke doing in military service in early 1941? pearl harbor wasn't bombed until dec 7. some of the hollywood community rushed off to service after pearl harbor, but this pre-war incident of active duty is mystifying!

david lean could create a great movie, the rest catch lightning in a bottle.