I guess you have not understood the pith of the discussion. It is clearly mentioned that all four categories will have their own exams. If a candidate is taking exam of the General cadre (PAS, OMG, IG, Postal Group,etc.), then why he/she would be given a seat from the other three categories. That's why I said that if someone was not allocated to PAS then he would be allocated directly to OMG, etc. And you started to teach me about the general preferences of the candidates.Anyway, it is you who needs to watch the video again.
Secondly, you said that there was no mention of degree specifics for the first three categories i.e., General cadre, Police Service, and Foreign Service.
Had there been similar degree required in all above-mentioned three categories, then both Police Service and Foreign Service would have been included into the General Cadre. It is absolutely clear that there will be different degrees required for different categories.