If a Muslim fakes a baptism, is he considered an apostate?

Think of a situation where a Muslim undergoes a baptism in a church in order to make Christians think that he's converting to Christianity (maybe he's doing some undercover work). But in reality, he is still a Muslim. Would that be shirk? Would that make him an apostate? I read that from the Islamic perspective, a baptism will have no effect on your faith. You still remain a Muslim. So I don't expect a baptism to be shirk if the intention is to make Christians think he is converting to Christianity.