P says that it’s useless to follow the new safety regulations at the lab. Why? Because the regulations don’t address the causes of a fire that happened last year, and so the regulations wouldn’t have stopped the fire or prevented any injuries.

Although not stated, Q’s argument leads to the implicit conclusion that following the new regulations is useful. Q says that any regulations that save money are useful, and the new regulations would prevent some accidents, thus saving money. This implies that, therefore, the new regulations are useful.

We need to find a point of disagreement. The usefulness of the new regulations is one such point: P thinks they’re useless, but Q thinks they’re useful.