This would have made more sense.

The bold invasion of the Vault for an Alien corpse from Roswell ultimately reveals... a fake. The classic alien as truly a ruse. The grey aliens are bullshit. Lending further credence that the Crystal Skull aliens were ultimately the true aliens. (still have no idea how there's so much evidence of potential aliens in ancient history and a story about a paranormal archaeologists doesn't delve into this.) Ancient alien history is a no brainer here. Indy should have come alive discovering it. Instead, we have a messy story with multiple aliens and no answers for either? What ever the fuck. Ya may as well have squeezed in hollow earth and lizard people. Anything goes I guess. That's my beef. They had an outlansish idea but they didn't commit to it. That's why it falls short. Show Indy clinging to a mountain while the shit hits the fan. We'll swallow it. But it was so damn confusing and weird.