Question: Professor Oberon (Bethany) is allergic to heat, sun, and sand. So why doesn't he die in the desert, like all the other characters do when they come in contact with their weaknesses?
Answer: He didn't die instantly because he didn't consume anything like Finbar did with the cake, his weakness to heat, sun, and sand is like the endurance he has and Finbar's strength and speed weakness it is simply a debuff on the character.
Question: What kind of vehicles were the guys driving while being chased by ostriches?
Answer: It's a Polaris RZR sand rail.
Can it be used on sand dunes as shown in the movie?
Yes, that's why it's called a sand rail. It's a similar term to dune buggy.
Answer: In the building with the Jumanji berry tree, there were flames on the wall. By following the flames on the wall, Ruby was able to get to the tree, rather than try to cross the waters somehow.
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