IMHO one of the aspects of search and rescue that doesn't get covered is the fact that things go wrong. Rescuers often become victims and need rescueing themselves. Even as the larger rescue has to go on.

To simulate this you might have every team connected by radio. Asign each person and resource a number. Every hour or two, at regular intervals, you roll dice for each person. If it comes up snake-eyes they have a problem you roll for.

Total of two six-sided dice:
2 - Both femurs broken. The team has to immobilize the legs and rig traction

3 - One leg broken. Immobilize.

4 - person is blind in both eyes. Bandage appropriately, document, arrange for a guide.

5,6 - Sprained ankle

Well... you get the idea.

If the roll says they are incapacitated and they are in a swamp or ravine when the call comes in they will need to be handled as if they were really injured. The command will likely need to keep a couple of crews and vehicles in reserve to to rescue the rescuers.

This also applies to vehicles. A roll of two or three means the vehicle is disabled. Four or five and it is incapacitated for an hour. Alternatively you could simply have them incapacitated and then roll to be repaired. Roll a six and they are up again.

The teams have to treat their own injured, transport them to a road and, if possible, continue to search their assigned area.

This tests the command structure as teams have to leave members behind to take care of disabled members and teams have to drop out, leaving jobs undone. Vehicles 'fail' at inopportune times and transport becomes an issue.

You should think about eliminating the use of GPS systems. For a real emergency the teams could have a unit sealed in a box and bring it out only if not using it would cause a real danger.

The idea here is to get used to the idea that things go wrong. But even as things go wrong the command structure has to keep functioning. This sort of exercise also gives a lot of simulated first-aid experience using what they have in their kits in varied field conditions as a simple grid search becomes a struggle to treat, transport, and take up the slack caused by the loss of multiple team members.

This can be done small-scale with just a half-dozen people and a search area the size of a large back yard with an exercise lasting just an hour. Or hundreds of people, square miles and several days. I would advise anyone start small and work up.

Smaller scale exercises can be hilarious with very high casualty rates. Jimmy to base ... I see the victim ... base to Jimmy I'm sorry but your right leg just broke. Nancy and Tom then spend ten minutes following protocols and splinting his leg. But half way through Nancy goes blind. It is a hoot when the rescue crews get everyone back to base with everyone more heavily bandaged than the original victim, who is often played by a dummy. Often crawling and dragging many of their number across the line.