Bennett University is completely safe & secured with security guards patrolling the campus 24×7 in shifts. Regularly police visit here to check control too. Also, BU is far away from politics or gang fights. Moreover, the University will not allow the students to go outside the campus after sunset (barring emergencies, that too in a car/taxi only) for the safety measures. Ambulance & doctors will be available 24 x 7, in-case of any medical emergency. You will feel completely safe & secured in the campus.
Coming to Greater Noida, it is normally safe for the students. The main areas are not isolated anymore & the crowd is increasing considerably and with metro coming up, it will see a huge uprise in population. The scenario has changed a lot during the last few years. You will see police vans patrolling the areas regularly. The security has been increased a lot too. Compared to a metropolitan like Delhi, the city sleeps a little early. I have returned to the hostel late two or three times due to traffic jams, and nothing happened to me. But I would not recommend you to visit any isolated area, especially at night. The public transport is quite good.