This reasoning is not correct. In this example, Bertie's boss convinces him of breaking the law in order to fulfill his order. Bertie does so, even though he is aware that this is a wrong action (this is clear from his surprised reaction and reluctance to carry out the order). However, even though Percy asked him to perform the action, Bertie would still be considered to be guilty due to the fact that he was ultimately the one who carried out an action that was illegal and dangerous.