First of all, you will not be allowed for BOM by KE as you do not have a visa. QR tickets are considered as seperate bookings ex-India.
You will need transit visa:
1. You certainly have to pass immigration as you will have to check-in with QR airport side desk located on 2nd floor.
2. You cannot use air-side transit as you have 2 seperate tickets, and are considered as pax travelling ex-India.
3. Air-side transit is generally designed for people booked on through tickets via BOM.
India is usually strict with Visas, and are never issued on arrival.