This side mission can be obtained from Sgt. Yeremeyev in the northwestern building of the Icarus compound, west of the Zaton region. Go up the stairs into Yeremeyev's room and speak with him, asking ...

After completing Arena: Round Three, and waiting a while for the Arena to be reset, speak with Arnie once again. Keep note that Arnie won't have the arena ready until you complete the Law and Order ...