Consider the following premises. For all x_5, x_5 will make tea. For all x_5, x_5 is not a taxi driver. For all x_5, x_5 is a taxi driver if and only if x_5 will make tea. Can we infer the following from them? If we can, name the inference rule being used: There is at least one x_5 for which x_5 is not a janitor.
The premises are contradictory and we can infer anything from them. Therefore, the answer is yes.