In the Hindu belief system, a marriage isn't like a social contract!! It's like an elaborate and strict religious procedure with very hard and fast rules where the priests look at the astrological map, built thousands of years ago, to find out the perfect time of the marriage ceremony to be officiated. Once that time passes you're done. Here, for some reason if the bride or the groom gets missing they need to find out the replacement ASAP, or they're like going to Hell....
*And, BD has volunteered to be a "wife" of India as stated by their Foreign Minister. If the real bride of India dies during the marriage ceremony then BD can be a suitable replacement