Dunlap, Dave Rowe and Shafer have driven Ted Sullivan out of the St. Louis Unions, and as he is on the black list his lot is not a happy one.-Cleveland Herald, June 18, 1884
You kind of have to take anything the Herald says about the UA or Dunlap with a grain of salt. But this is the best piece of evidence we have about what went down between Sullivan and his players.
Regardless, Sullivan would land on his feet and be back in baseball, with the Kansas City Unions, in July. And thinking about that fact, that Sullivan would get another job in Lucas' UA, leads me to believe that it really was the players, rather than Sullivan, who instigated the whole thing.