This sounds like possible overreach on behalf of both the plaintiff and Disney. I'm uncertain how a failure by what I suppose is a tenant restaurant becomes the responsibility of the leasing party, in this case, Disney. It seems like the common strategy in liability cases to sue everyone in sight.
On the other hand, the proposed defense and resort to what would seem to be an unrelated arbitration clause in a seemingly unrelated transaction would be only further temptation to impose arbitration for almost all transactions with a party for any reason forever after. The pernicious creep of arbitration already threatens the rights of individuals to pursue legal action in many, perhaps most, dealings with corporations imposing terms of service.
Big Al