One of my friends studied at PGIMS Rohtak. According to him, there are a lot of perks of being a student here.

• It has a high patient inflow with 6000-7000 patients daily in OPD. This is the result of the reputation the doctors have earned in the last few years.
• There are well-equipped labs, well-to-do apparatus, good guides, a large D-hall with the required number of cadavers and specimens, an anatomy museum with almost all models, Histology lab with good slides. 
• The auditorium is large and has good capacity, beautiful architecture. 
• The faculty is overall good, they have a good amount of clinical knowledge and great experience.
• Major fests like ARMSCON and XTASIA are held every year where med students from all Haryana colleges come and participate.
• Other than that, events like sports meets, conferences, celebrations on various occasions, festivals, etc. take place.
• All hostels are well maintained and cleaned regularly.
• Mess food is average. There are 2 canteens.

They also have contributions to rural health services and slums, they have organizations like NMO (for rural areas) which includes different programs, and MSC (mostly for slum areas). They work on a regular basis for the maintenance of health in these areas. These will also be beneficial for your career.

Yes it is possible. There are a lot of mediocre students who evolve with time and end up cracking IIT or AIIMS.

• AIIMS conducts an entrance exam every 6 months for entry into its MD, MS courses. 
• You can regularly visit the exam portal of AIIMS to check for all the details regarding exam pattern, eligibility, seat distribution, registration for the exam, and other details. 
• They also release exam notifications in newspapers.
• AIIMS generally reserves 50% of its PG seats for its internal candidates (those who have pursued their MBBS from AIIMS), which doesn't mean external candidates don't stand a chance.

Since MD radiology at AIIMS, New Delhi is your target, you will require a rank in top 3-5 to secure a place in MD radiology. It might be the toughest exam but it is not impossible. Try dedicating more time preparing for this, which might give you positive results.