He held all the cards when we were still in the process. With us out he can walk away but he will have one really pissed off player, so that takes away some of his leverage.
He won't walk away but he may slow the deal down and make them nervous. Plenty of time to make it happen on his terms. Arsenal will want to have Rice as soon as possible in order to integrate him in the team and start the season strongly. Sully is in a good position, no need to give up on his demands yet.