Three instructors and their students are on board a dive boat
in the middle of the ocean. There is a NAUI instructor, a PADI
instructor, and an SSI instructor. Everything is going fine until
the boat springs a leak and starts to sink. The SSI instructor
says to his students, "Okay, we're in the middle of the ocean,
so we might as well do our deep dive." The NAUI instructor
says to his students, "Okay, we might as well do our
navigation dive, so let's get our compasses out and swim
towards shore." The PADI instructor says to his
students, "Okay, for RM25 extra you guys get to do a wreck 
dive!"