Yes, you're right....Suman shook her head negative when Shravan was going to fall back....even she knows that Anish is not trustworthy. The only problem I had with that scene was that she wasn't seen speaking up the truth whereas previously she would always stand up whenever she saw something wrong. She's alway moral-policing Shravan but not her friends who she has known for years and keep doing things that are not acceptable.
She has her points for doing it...if you noticed she was watching him all the way through......She tries to correct Shravan because she cares for him... to some, extent.....her dad also given her that responsibility...Anish & Devika are her classmates cum friends but not besties......kids like Shravan can't be trusted easily......at least his pre-break traits...