I think Rachel always pushes Baam away to make herself the heroine of the prophecy and make it her destiny, even though the prophecy is about Baam. Rachel is inherently a selfish character and does things without thinking how it’ll affect others. Because she is weak and average, she has to use the strength of others to build herself worth to more than what it is. Its also a reason why she treats the Baam the way she does, it’s to make him hesitate in his decision to hate her even after all the horrible things she’s done to him.
I think she’s afraid of the night because it swallows everything in never ending darkness.(since its a play on words in Korean, I think we as English readers may miss nuances that aren’t able to carry over well due to translation, but I think the concept of nighttime and darkness is important in understanding Bam’s abilities and Rachel’s fear) I, personally don’t think that Rachel is literally afraid of the dark (because she found Baam in a dark ass cave) but what’s in the dark/night. She’s unable to see it and therefore can’t prepare for the unknown. She’s a cautious character that rarely acts out of plan curiosity and always plans to keep herself safe. She’s not adventurous, so it explains why she chose the lighthouse position (due to her manipulative nature, I think she feels the need to be in control of everything or needs to be hyper aware of what’s going on) and her base strength hasn’t improved since she starting climbing the tower.
By applying the concepts of darkness and nighttime to Baam, it’ll make sense as why she hates him so much. He has boundless potential, which “swallows” any technique that he’s hit with, and his inner world (I guess) there’s a huge light behind the humonid figure ( guess is Bam’s true power) and its basically described as a blackhole.
The only reason why is able to be in the tower is because Baam open the door on top of her by mistake, this causing both of them to fall in. In the flash back, Headon only let’s Rachel to climb the tower after trying to kick her is due to a deal that they made. Rachel is the most irregular irregular, due to the fact she’s a misplaced citizen there due to her own greed and ego. Its the reason why she stays so weak, even though her peers are always getting stronger. She has no means to do so, since she possess little to no power whatsoever.
A lot of people like to think that the cave is some sort of resurrection chamber, where Baam needed to stay to recover from his death. This would explain why he is in a cave even though he avandoned the tower with his mother, the same mother that carried his “cursed” body around during years and didn’t let him go.
I think that to talk about the outside, first we have to understand what it means for the people inside the tower ‘the outside’. For the inhabitants of the tower, ANYTHING that is NOT the tower can be considered the outside. This includes any type of possibility which could also be a place where you don’t have access to the great sky and the stars. Even the tower could be inside another tower.
It’s pretty clear that Rachel was in a strange place, it seems she was closed and trapped like Baam, I don’t know where, but it was a place big enough or guarded enough to not let Rachel even think of leaving. It’s almost like if the only way out of that place was to first enter the tower and then reach the top. I guess the impossibility to leave that place was the real deal if she thought it was easier to climb the tower than trying that. I think a wonderful situation would be if outside Baam’s cave there was just another giant cave.
I don’t think Rachel could get access to the cave by chance, it seems a very important place with a very important person to left it unguarded. Also we have the fisrt scenes of the series where we see Baam with his custom-made clothes and a big knife. I don’t think these are things that Rachel could create or even buy by her own. I think the only part that was planned by her own means was how to leave that place.
I think Arlene had to pay a price to leave the tower and revive her child to carry on the prophecy, and having to give up on seeing the stars again could be part of the deal, so the God of the outside sent her into a place outside the tower where she would never be able to see the stars again.