Even if they were buddy off and her buddy did see it, what is he supposed to do? So they were told about buddy systems, so what? Some agencies do not train any assists much less underwater or surface emergencies or rescues until after an advanced course. That makes a lot of sense, sombody had a bright idea about progression of training HA. Until that time they are only told to dive in buddy teams but are clueless what to do. If they would try to react, most likely they get themselves into trouble also.