Clearly, Dick still didn't understand Donnie.
When Donnie decided to acquire Breton Bank and negotiated, then cooperated, with Morgan and Mellon, this signified Donnie's resolve to take control of Breton Bank at all costs.
So, unless Dick was willing to relinquish all his shares in Breton Bank and cleanly break away from it, there was no way Donnie would give up on the acquisition.
Thereby, Dick's attempt to negotiate with Donnie this time was clearly fruitless.
Donnie did propose to buy out Dick's shares in Breton Bank, but it was improbable that Dick would let go of the bank, leading to their negotiations inevitably breaking down.
Left with no other choice, Dick left Atlantic City and informed Laze Madison and Archibald Roosevelt of the outcome, "A big fight is now inevitable!"
The two could only express their helplessness at this outcome, but they had their moves to make, which was to quickly buy up shares of Sinclair Oil Corporation on the market.
