Missionary

The house still has to run.

When someone is serving, the rest of the household is the 72-hour kit, the out-of-area number, and the people who get the call.

Keep the mission office / apartment address and emergency numbers in the printed plan — not only on a phone.
The household still needs a 72-hour kit and an out-of-area contact while someone is serving.
Packages: meds they actually take, socks, and a letter beat clever gadgets.
If a local disaster hits while they are out: you handle the house; they follow mission rules. Don’t invent a private extraction plan.
When they come home, put them back on the plan the first week — phones change.