I think people have to take account that Rachel had a life before she enter the tower. Outside the tower(TUS) exis/exies(plural) who are common outside the tower are 10x stronger like with Phantaminum being ranked top 5 exis. Maybe or maybe not that plays a role on why she's desparetly trying to climb the tower. Also there was a war that probably could of traumatize her. Each character like Koon, Anak or Love have their story, but I don't think it compares to exis that are god-like in (TUS).
Off topic I wanted to throw this out there whoever read the (TUS) info.
Exes are known for the title of King. Conquering King, King of Artificial.
Zahard (King of the Tower) could he possibly be an exis and that's why Phantaminum visit him?
No,the only exis in TOG is Phantaninum and we won't even get to see him.Siu said that.So Zahard is a simple human immortal and irregular.But no God.
Reread chapter 76, you will see that Headon was waiting a particular guest, he was waiting the person chosen by the Tower, and he knew for sure that Rachel wasn't the good person. For some reason Headon knew Baam's characteristics and could compare them to Rachel's characteristics and tell that she wasn't the good person. He even knew Rachel's psychology as if he could read into her mind and could tell ''how loathsome, dirty and dreadful of a person'' she was. We don't know how he is able to do that but we just have to admit that Headon has this kind of power.
So, Headon was sure the Tower choose someone else than Rachel and was surprised to face her. He had no reason to lie, he told her straight that she wasn't chosen by the Tower and she didn't have the qualities to climb the Tower. He didn't want to test her, his mission is to test the people chosen by the Tower. If she didn't beg him, he would have asked her to leave and it would have been the end of her story.
After that, chapter 2 (yes 2), Yuri makes her apparition and we can see that Headon is surprised, he says ''oh ho, this person is … '', and we deduce that he is not (completely) omniscient and prescient. Even if he seems to be a God, actually he can't anticipate that much and has to analyze the things as they happen and elaborate plans according to the situation. It seems pretty clear that he didn't expect Rachel to come into the Tower and he didn't think she could be of any use to him, but in the end he thought he could use her in relation with Baam.
Hmm..where to start.So..you think that Headon was waiting a specific guest and it only took some begging to try someone else?Only with some begging anyone can try to climb the Tower?Even if he thought she would fail,I find it hard to believe that she would even be given the chance to try...then that specific guest..how do we know it wasn't two guests?Why would it be only one?
Why do you have so much trust in the honesty of Headon.He lied to baam to push him to climb and join FUG.He lied to Lahel to crush her,and make her betray Baam and also join Fug.With some little lies,and voila!Two irregulars in FUG.
As for chapter two..don't you find it a little suspicious and strange that Yuri somehow learned and came down?Noone else seems to know not even RED or Zahard or Urek and Wingtree.But Yuri??How?Not even her guide,the high ranker guide of the royal family didn't even know.
And then after some time ,we are conveniently introduced to a strange character.Someone who could have known,since she has one of the strongest lighthouses in the world.Someone who easily seems to manipulate Yuri to achieve a goal,and someone who seems to knowww a lot and have some shady connection with FUG.Repellista.
That's how conveniently Yuri learned about the irregular and came down.And Headon ofcourse acts suprised.But does he stop them from interfering?This is a floor test afterall rankers shouldn't interfere!...if they are not supposed to.If Headon hadn't planned for Yuri's interference and wasn't in his plans you can bet he wouldn't let her even get close to Baam.