For two hours yesterday, service on the New York subway's B and Q lines was stopped in Brooklyn as transit employees searched for two kittens that got down near the third rail. Kittens are now safe. Now you may be prompted to do some kind of cost-benefit analysis about kittens versus lost productivity of stranded train riders. Before you do, consider the photo The New York Post took of one of the little guys, peering out w ith his fluffy face and green eyes, his little nose obscured by the track. Where's that fit into your ruthless spreadsheet?