if u have a connecting train from HWH or lot of time to kill and hungry, just slip into the food plaza(operated by Monginis) in old complex(terminal-1). It's a multicusine food court which serves excellent food starting from crispy dosas with well done chutney(as good as of a good south indian eatery), chole bhature, noodles, chicken curry, fish curry, grilled cheese sandwiches, snacks, sweets to fresh fruit juices and lassi. Its restroom is very clean, light years better than those at the first class waiting room.
Ps- it isn't the Comesum of new complex(terminal-2)