“Now tell e/o what’s the difference between the two cases!”
Ubiquitin already explained the difference very nicely a few posts up. Though I’m still not sure I agree fully, because one of his main points is that CPR is easier to learn that flying a plane, which is true, but it is still not easy enough. The level at which most people learn CPR is not really adequate to help in a real life situation, and to expect them to learn more than that is unreasonable.
“but there is a Chiyov”
Is there really? Maybe there is a chiyuv to become a doctor and a firefighter also.