As a serving Naval Officer (and ex-Naval Pilot) I think you would be mad to turn down the chance of a commission! 4 years is nothing and would place you in a superb position with an airline.
For example I was recently chatting to a very well known FTO because I was worried about my age (31 going on 32) and the chances of getting an airline job post training. The chap at the FTO advised me that as an ex-Naval Officer with a PPL and an engineering degree that I was an airline's "wet dream" !!! Yes he was obviously tring to sell me a course of training BUT do not underestimate how much Kudos the airlines place on military service (whether it be commissioned or not).
Go Army, continue flying on the cheap through any number of service flying clubs (RAF BENSON club £63.50 p/hr wet for C152) and then complete the modular training.
I wish I was 27 and in that position!!!
Good luck
MFWF
