Laurel had to face is own worries before heading straight to a battlefield.
He needed to take the restrains his body imposed him to work with them and live as normally as possible. He pictured them like chains but now that he was peacefully walking outside, without any order to follow or rules to apply, he changed his point of view.
He needed to make a force out of it and adapt his situation to the 'gift' he was bestowed upon, as he always did before. This time, he had to go forward willingly. Clenching his fists, he embraced the role he had to assume and lost himself in thoughts.
He wasn't alone anymore, he wanted to give back Oswald the brotherly sensation he felt when paid attention to, when training, when saved, when he had a simple conversation. He was given much more than regeneration abilities. He had strength and will anew, he was given enough power to fight back against every threat he could think about.