The Bible doesn't offer a definitive answer to this specific scenario. Interpretations of the Mark of the Beast and its consequences vary widely among different Christian denominations and biblical scholars.
Some believe the Mark is a literal, physical mark signifying allegiance to the Antichrist, and that taking it, regardless of one's belief in Jesus, would result in eternal damnation. This perspective emphasizes the seriousness of rejecting God and aligning oneself with evil.
Others view the Mark more symbolically, representing a spiritual commitment to worldly values and rejection of God's principles. They might argue that if someone takes the Mark due to deception or coercion, but maintains genuine faith in Jesus and repents, they could still be saved. This perspective emphasizes God's grace and forgiveness.
Ultimately, the question of salvation is a matter of faith and God's judgment.