One does rather wonder, at times, whether PJIs oughtn't to be, for example, serving members of the paras who, for example, stroll down the back of the plane and jump out yelling 'follow me'.
Actually, in all honesty, I have never yet understood why the RAF has PTIs at all - during my service I just rather assumed the recruiting offices had some sort of remit that required them to sign up wannabe male models, and the PTI school was where these people were then sent.
I always thought they were quite unbalanced, frankly.
Dave