Complete
Your fingers before were complete.
Imagine one of your fingers is missing, and they're no longer complete like before. When everyone told you not to join that yakuza gang, you just didn't listen.
せん
そろ
None
To have your complete fingers back, you gotta run to the hospital solo (そろ).
You can't be seen with anyone because your former yakuza mates might be watching you. Seriously, you don't want anyone else involved in this business.