can we drop out of integrated msc course with just Bsc certificate in gndu
No. The degree is a dual one and you can NEVER get a single one if you drop. This is clearly stated in the university curriculum. This is why lateral entry is not allowed in integrated courses and you cannot drop out in middle once you have joined you have to complete it to get the degrees you cannot just bail out and ask for a single degree. You can even enquire in your university for more details.
Hope this helps you