In an emergency situation, determining the best route to leave that situation and head to safety is extremely important. It may involve changing plans repeatedly to react to new dangers or changing circumstances. For example, in a bushfire, new areas may be affected meaning that the planned route becomes impassable.
The best planning for an emergency should occur prior to starting on the trip. Escape routes and detours should have been factored into the route plan. Falling back on this knowledge should provide options if faced in an emergency setting.
However, if these are not an option due to a changing circumstance, then the group will need to work together and come up with a decisive plan to effectively navigate their way to safety.