"One of the worse worse worse things bystanders often do is pull objects out of patients. i.e. if you are stabbed, and the knife is still in you - do not pull i

"One of the worse worse worse things bystanders often do is pull objects out of patients. i.e. if you are stabbed, and the knife is still in you - do not pull it out." When I had my last first-aid-course, the instructor told us exactly this - do not pull out the knife. And then he added: but if you did and you realize your mistake, do not put it back in! ;-)