Why is Mihno so hostile to Thomas

I think that Minho wants to assert his influence. He gets angry whe Thomas questions him. Minho accosts Alby in a manner that Thomas has not seen anyone ever do. Alby turns and runs off, presumably to fetch water. Thomas asks how it is that Minho can speak to Alby like that. Isn’t Alby the leader? Minho dismisses the notion, calling Thomas a Greenie.