I think it's the same at any Indian medical school, the purpose of class is attend and is a matter of self discipline to get your mandatory attendance in the eyes of teachers. You don't pick up much in class, your expected to learn the bulk of it during your own time.
Its a complete 180 from undergrad/medical school, where the teachers teach you the concepts during class elaborately, which makes your reading the following day much easier.
I really would suggest doing at least 1 year of undergrad and see how it goes before coming here, just simply for the maturity experience. It may seem like a waste of time and money, but you will appreciate it after you complete the year.
Admissions for NRI seats is very competitive by the way, demand has been increasing every year, so I wouldn't count this school as a "backup", it's hard to get in to begin with. Its is due to people with deep pockets, not necessarily because of the caliber of the student.