Factual error: A piece of ship that size crash landing into a planet and not being destroyed would be an extinction level event. The asteroid that supposedly killed the dinosaurs was a lot smaller.
Factual error: After the speeder chase the gang lands on quicksand. Not only do they not sink into it until after the stormtroopers are dealt with, but they suddenly sink at great speed. On top of that quicksand is heavier than air so there is no way that it could have floated and formed the roof of a cave like that. It would simply fall in and sit on the floor, in point of fact it would never have been able to sit like that at all.
Answer: Palpatine has been manipulating Rey and Kylo Ren from the very start, bringing the pair together and instigating fights between them. He is trying to make Rey stronger so that when he takes over her body, she will be powerful. Palpatine can partially see the future and knows that Kylo will not be successful in actually killing Rey, but that their constant fights will cause the two to grow more powerful. Because he can see part of the future, he knows that eventually Rey will triumph over Kylo and "kill" him, and then come to confront him directly. He doesn't count on Ben Solo coming back to face him which winds up being his undoing.
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