Noel had enough of being stuck thinking. He needed to act. Having no change was death in itself, stagnation.
And he would rather die a quick death than stagnate.
The same monotonous state was not for someone like him. This must be part of the reason why he could not handle acting the same way as Leon, who was as monotone as could be in his eyes.
He always liked the same things, do the same routine, keeps the same beliefs for years and years and years.
Noel was the opposite, and can get sick and tired when things were constant, like water all around him that stays as water forever. Just drowning in a sea of monotony.
Life felt that way. Being human felt that it shouldn't be like this.
He wanted to feel human, even in destructive ways that would make him explode. Staying in the
middle, waiting for results...
That's just not how he is.
So...
He stopped breathing.