Three instructors and their students are on board a dive boat in the middle of the ocean— there’s 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 $25 extra you guys get to do a wreck dive!"