Attempt Number: 4
Error Message: Action not unique compared to other actions chosen from this state before. Choose a new action

Action Reasoning:
The next action in the plan is to move down fast1 from n2 to n0, which will allow p3 to leave at its destination.

New State Description:
- fast0: At floor n0, 0/2 passengers.- fast1: At floor n0, 1/2 passengers (p3 on board).- slow0-0: At floor n0, 0/1 passengers.- slow1-0: At floor n3, 0/1 passengers.- p0: On floor n0.- p1: On floor n1.- p2: On floor n2.- p3: On board fast1.- p4: On floor n1.- p5: On floor n3.

Action Chosen:
(move-down-fast fast1 n2 n0)
