With Solo Leveling season 2 slowing inching toward the Jeju Island Arc's conclusion, fans only have one question: why didn't Sung Jinwoo go to Jeju Island sooner? As suggested by the latest episode, the protagonist was prepared to head into action at a moment's notice, so it did not make sense why he didn't assist the other S-Rank Hunters much sooner.
Sung Jinwoo did not go to Jeju Island sooner because he did not believe the Hunters needed his help until much later. Jinwoo believed the S-Rank Hunters were strong enough to defeat the Ant Queen. Thus, despite the danger and potential to gain a lot of experience, Jinwoo prioritized his family.
Why did Sung Jinwoo refuse to partake in the Jeju Island Raid in Solo Leveling season 2?

As revealed in the anime, Sung Jinwoo chose not to partake in the Jeju Island Raid to spend time with his family. His mother Park Kyung-Hye had only recently recovered from Eternal Slumber, hence, despite the possibility of attaining massive amounts of XP, Jinwoo prioritized his family.
That said, this reasoning does not truly feel sound from Sung Jinwoo's perspective. This is because, if the S-Rank Hunters were to fail the mission, it would also mean endangering all of Korea, including his family. In reality, Sung Jinwoo never thought that the S-Rank Hunters would fail the mission.

After witnessing the S-Rank Hunters fight each other and having a one-on-one battle with Goto Ryuji, Sung Jinwoo believed that the Korean and Japanese S-Rank Hunters were more than capable of completing the mission on their own until everything went according to plan. Surprisingly, his assessment was never wrong.
As per the plan, the Japanese Hunters were to distract the Ants, while the Korean Hunters would enter the nest and go after the Ant Queen. As planned, the Korean S-Rank Hunters killed the Ant Queen. The only mishap surrounding the plan was the Ant King's sudden appearance, which was a development no one could have predicted.

As for those fans questioning why Jinwoo did not join the fight as soon as the Ant King appeared, the truth is that the protagonist had no way of knowing what was going on in Jeju Island. As revealed by the A-Rank Hunter who had joined the S-Rank Hunters, their broadcast observed a 10-minute delay to conduct any edits. So, even if Jinwoo were to watch the broadcast, he would have been too late.
Therefore, for him, the only way to identify any mishap during the mission was with his Shadow Soldiers. As fans must remember, Jinwoo had planted his Shadow Soldiers within the shadows of Goto Ryuji, Choi Jong-in, Cha Hae-in, Go Gunhee, and Baek Yoonho. So, unless one of them had passed away, Jinwoo had no way of learning whether the mission had taken a step for the worse.

This is also why Sung Jinwoo did not join the fight when Min Byung-Gyu passed away. The S-Rank Healer had only joined the rest of the Hunters on the mission day, hence, Jinwoo never met him. Thus, Jinwoo only joined the mission after Goto Ryuji met his demise.
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