Indeed. And as you say, the Bible doesn't really answer this question. On the one hand it says if we deny Jesus before men, he will deny us before God in heaven. On the other hand, it says God looks at the heart, and that not everyone who calls him Lord will enter the kingdom of heaven. Surely that means there has to be some wiggle room here, when looking out for the interest of others. What would Jesus have done? It's impossible to know, because he didn't ever face that situation, as far as we know from scripture. It's an impossible question that I pray to God I am never, ever faced with.