Alexander left right after Noah devoured as many ethereal magical beasts as possible. He only remained outside the trial to give a series of directives and goodbyes to his companions before approaching the test and disappearing behind the large metal door at the end of the corridor.
Noah felt weak. His mind had enlarged quickly, and the energy inside the head was improving his body at a steady pace. Yet, he felt drained and frail.
'My mental walls have reached their limit,' Noah thought while inspecting his condition.
Devouring ethereal magical beasts thinned his mental walls and made him uncomfortable about his current condition. Noah knew that he couldn't fight in that state. A mistake during a battle could make his sea of consciousness crumble right now.
It was rare for Noah to decide to put himself in such a poor condition, especially when he didn't gain clear improvements in battle prowess in exchange for those drawbacks.