My hubby has one hard fast rule, if he hears thunder golf is over for the time being or the day. He will head for the club house and that's that. I would follow the advice that says use the cell and call for an Ambassador or walk to the nearest house. Those fellows were demented to remain on the course. I once met Lee Trevino and his story of being hit by lightening was horrible. Why anyone who lives here in the Villages where you can golf pretty much every day would remain on the course in a storm behooves me!
Make new buddies if these are "friends" and if you just ended up with this foursome, remember their names and decline to play in their foursome again.
I am surprised that the Ambassadors didn't come out to get people off the course!!!!! :

???