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 board passenger p0 onto fast1 at floor n4. This action is the next logical step to progress toward the goal state.

New State Description:
- fast0: At floor n0, 0/2 passengers.- fast1: At floor n4, 2/2 passengers (p5 and p0 on board).- slow0-0: At floor n2, 0/1 passengers.- p0: On board fast1.- p1: On floor n1.- p2: On floor n5.- p3: On floor n5.- p4: On floor n2.- p5: On board fast1.- p6: On floor n2.

Action Chosen:
(board p0 fast1 n4 n1 n2)
