Unlike Alina, Ashton didn't have a clear goal in mind, nor did he know what he was searching for so desperately. He only knew there had to be something, a hint or likewise, to help him discover more about his father and his connection with Phantom.
However, it was a bizarre situation as Ashton had no idea where his father could have left a clue for him to find. That was why he decided to disguise himself as the Chief and get unrestricted access around the facility.
Before sending Mikosh off with Viper and Alina, Ashton made sure to pull some information out of him about his father. Sadly, Mikosh had only been recently employed as the Section Chief and had no idea where Ashton's father could be.
However, the undead disclosed some helpful information, such as the part of the facility where Ashton's father should've stayed as a prisoner from Lycania.