First off, he knows that Santu means the world to Nanaji and Family, second off he know it will be a big blow to DM's ego if he were to cause harm to someone living under his roof (so to speek), considering that DM was angry last time becasue Virat took Santu (the wedding) even though he didn't care about Santu in particular, but the fact that her name was attached to his mattared, therefore I think Santu SHOULD be the target (if Virat needs one) because as we all can see, DM is sorta getting mushy around her, so it would be this whole new dimension....and plus Hiten and DM might team up to get her back, hence making Khemi all ohlala over Hiten..