I've read or seen three debates in which Mike Licona uses the same illustration: if the audience witnessed him beheaded on stage, then ten minutes later he emerges outside restored to life, and says that while he was in heaven God revealed to him a private conversation with an audience member, to which only the audience member would be privy, would an atheist admit that this was a miracle?
He's using this hypothetical as a wedge tactic to test how fantastically devoted an atheist is to rejecting miraculous explanations. Is there absolutely nothing they'd accept as evidence for a miracle? However, I don't think this is a good illustration to prove his point:
1. Atheists often try to lampoon miracles by concocting preposterous hypotheticals, then ask how you'd respond if your best friend told you he saw that. But biblical miracles aren't equivalent to weird events: biblical miracles are purposeful. They often have a symbolic function.
2. Given what we know about professional magicians (e.g. sawing a lady in half), it would be more reasonable to conclude that the apparent beheading was illusory rather than miraculous.
3. In addition, that's not analogous to biblical miracles like the Resurrection. Appearing to saw a lady in half are elaborately staged, with trick boxes and trap doors, &c. But biblical miracles like the Resurrection did not and could not be staged like that. It wasn't a controlled setting with elaborate preparations and special equipment.
4. In addition, Jesus reportedly appeared to many people at different times, locations, angles, and lighting conditions.
5. In fairness, Licona added a veridical element regarding supernatural or paranormal knowledge about a private conversation. However, that's logically independent of the beheading hypothetical.
6. That said, in both debates, Licona's atheist opponent took the position that it's more plausible, or at least as plausible, to conclude that recovering from decapitation is naturally possible than to concede a miracle. Yet atheists routinely deny the possibility of miracles because they define a miracle as a violation of natural law, and they treat any alternative explanation as more plausible than breaking a nature law. Problem is that atheists try to have it both says:
i) A reported miracle didn't happen because that would break a natural law
ii) If it did happen, that means it was naturally possible after all.
But that's a heads I win, tails you lose gimmick.