Specialist idea: Mercenary

I have an new specialist idea. It was originally going to be called a deserter but after thinking about his effect for the deserter I felt this would actualy be a better mercenary (I am still working on the deserter though).
Mercenary
Local: destroys 10 drillers for every specialist in combat (including your opponents). Every 6 hours you must pay him 10 drillers from the sub or outpost he is at or he will travel to the nearest enemy outpost and join thier empire.
The mercenary give you a massive advantage when attacking but he can be like playing with fire. I did some math and he would destroy 30 drillers with a full sub not including you opponents specialists. He in 24 hours destroys 40 drillers so there is a loss of drillers at best so I feel he is balanced. What do you think?
Mercenary
Local: destroys 10 drillers for every specialist in combat (including your opponents). Every 6 hours you must pay him 10 drillers from the sub or outpost he is at or he will travel to the nearest enemy outpost and join thier empire.
The mercenary give you a massive advantage when attacking but he can be like playing with fire. I did some math and he would destroy 30 drillers with a full sub not including you opponents specialists. He in 24 hours destroys 40 drillers so there is a loss of drillers at best so I feel he is balanced. What do you think?