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 at depth 6 is to move fast1 down from n4 to n2, as it aligns with getting p2 and p3 closer to their destination floors.

New State Description:
- fast0: At floor n0, 0/2 passengers.- fast1: At floor n2, 2/2 passengers (p3 and p2 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 board fast1.- p3: On board fast1.- p4: On floor n1.- p5: On floor n3.

Action Chosen:
(move-down-fast fast1 n4 n2)
