"2. If possible, rescuers should always try to have a "Plan B" for evacuating the victim. It is often wise to launch the ground ambulance even if you think you can use a helicopter."

Absolutely! I have fond memories of the occasion when, the helicopter having just gone into a hover ready to hoist our victim out of a deep wilderness situation, the pilot announced that he had just gotten a red light on his panel (something to do with his rotor mechanism), he was going to leave, and would return as soon as everything was airworthy again. Indeed he did, a couple of hours later.

Helos are absolutely wonderful, they save lives and a lot of very hard work routinely, but yes, you always should have a plan B ready.