SHOULD U DENY CHRIST (w/o conviction) TO SAVE SOMEBODY ELSE? "Christians in Syria Struggle to Survive amid Terrors -"

This article is about a Christian father who was told by ISIS that if he didn't deny Christianity & return to Islam,they would kill his son. The father refused, & ISIS subsequently killed the kid. My question is whether it is ever okay to make a fake denial of Christ for the sake of saving a life? It would be a lie,yes. And lying is a sin. But so is murder. Isn't it okay to sin to prevent a greater sin? For that matter,even if its not about saving another person's life,but just your own,would it be justified to make a fake denial of Jesus Christ to keep yourself from being killed? It goes against our notion of heroic self-sacrifice,but if we stay alive,aren't we more valuable for the kingdom? In the mideast world where ISIS roams,if u make a fake denial of Christ and a fake affirmation of Islam for the sake of staying alive (and prventing the much greater sin of murder,of yourself) you could operate as an "underground Christian". Is this contrary to God's code of expectations or would He applaud our savvy modus operandi?
http://www.christianheadlines.com/news/christians-in-syria-struggle-to-survive-amid-terrors.html