While many may consider Derik and Cyrus' actions as unreasonable and reckless, no one could deny the fact that it was necessary. While the risk of dying before their breakthrough is quite high when facing off against the orc overseer, this is the only option they have if they wish to protect the empire.
At this point, everyone knew waiting for them to reach the demigod realm was not an option anymore. Once their breakthrough is complete and they reach the demigod realm, they will be forced to leave this world. During the period they are away, nothing stops the overseer from returning and destroying the empire with just a snap of its fingers. For that reason alone, Derik and Cyrus chose to provoke it and have it come for them while they were still mortals.
This is a problem they must resolve before breaking into the demigod realm!