Considering Ijin's entry during the fight between the Numbers versus One and 003 has two factors:
- If it escalates, One probably uses the "attack the family" method to capture SW. And that includes capturing Ijin's family as well.
- Ijin's actions prevent SW from accidentally attacking the Numbers. I don't doubt that SW might be monitoring everyone's movements, whether it's One's or the Numbers.
I imagined the script was originally going to use the "attack the family" plot, but it's good that it went in a different direction.