Peoples always try to weasel out of their service during basic/boot training. An Army Chaplin friend of mine, said that they had each excuse numbered, because they all came up with the same/similar excuses. (i.e. daily schedule 10am counsel pvt jones excuse # 3, 11am pvt smith excuse #2, etc)
So I wouldn't put any great weight in their excuses. Especially being in the navy, its not like they would be getting shot at in the front lines (unless they're a med corpsmen or chaplin's assistant attached to a marine unit.)