One thing that my dad and grandfather always did was ask simple questions that made us think. I do it with my son and the other boys in my troop to this day. You can use the technique virtually anywhere. Things like:
Dinnertime at the table, "what would you do if you saw me starting to choke?"

Taking a walk, "imagine that I fell and couldn't get up?"
Driving up north skiing, on a long stretch of isolated road, "what if the car ran out of gas here?".

Later, skiing, "what if you went off the trail into a tree and broke a leg?"

You're walking back from fishing: "What if you and your buddies take the shortcut from the fishing hole at the lake and miss a turn, it's now dark, and you don't know where the trail is, what do you do?"

Learning is forever on preparedness. It's great that you're starting them young, and the good news is, you never stop. One day, they go away and you hope you've done the best you can. Hopefully they make it long enough so you can do the same for your grandkids!