during the challenge sous chef Aaron can be seen giving advice and instruction to the contestants, therefore demonstrating favoritism.
In the final round of the black jacket challenge, to avoid demonstrating favoritism Ramsey had the 4 contestants sample dishes cooked by the last 2 contestants without telling them which contestant cooked either dish, when he told them after they sampled and before and they voted, contradicted his intention from the beginning which was to avoid demonstrating favoritism.