You are advocating openly denying the Savior to save your own skin...at the peril of your soul. You're kidding yourself if you see it any other way. One cannot deny Jesus with a wink and a nudge to make it into something else. To follow Christ we need to emulate Christ, correct? At what point did Jesus say "I'm just kidding folks...I'm not the Messiah. Just a joke." That's what you're advocating.
It’s called survival. When dealing with someone trying to kill you, lying to your captors is not a concern. Yourself, your faith and your Deity will know the truth. Forfeiting your life for spoken words makes any future words meaningless.
Telling some islamo nutcase what he wants to hear is no worse than telling a dog you won’t kill it when he takes his teeth out of you so you can reach your weapon.