Two sister missionaries in Southfield, Michigan, Sister Adams and Sister Rambert, were woken early Sunday morning when their carbon monoxide alarm went off. Deadly gas began filling their apartment, coming from a faulty water heater, according to Fox 2 News.

As they called 911 and started to leave the building, the sisters quickly realized they were the only ones with a carbon monoxide detector in the Cambridge Square apartments.

So these missionaries did what they do best: they went door to door. But instead of sharing the gospel, they were saving lives.

Read LDS Living’s report here and see the full story at Fox 2 News.