It was indeed unfair to Dips and Srishty, on both BB and Romil's parts. Romil clearly knew that had he discussed what he wanted to do with Dips and Srishty, they'd have protested and said if he's willing to forego his chance then it should go to another of thier trio. So he waited, and then asked BB. Their is no spinning that ultimately Dips and Srishty sacrificed for Somi - which was not thier choice.
From the game point of view, Romil did well, because, with BB's help he achieved what he set out to do. But personally, I don't agree with what he did. If he wasn't going to use the chance he was given, then it was owed to Dips or Sristhy, task-wise and more than Somi, for sure. And in any case, while I don't deny that Romil sacrificed for Somi, his was in no way greater than the others', the way it was portrayed.
What's telling IMO is that BB bent the rules for Romil - on a previous instance of mahaanta, BB chose jail, noms and weekend pe bashing.