Guys please calm down, its a show and the characters are not real. Its written by the writers for a channel and made in such a way where the more it runs, the more money everyone makes and for that they have to show as much as fiction as they can.
Every character has positive traits and negative. If you show only positivity unfortunately the show wont run and will be taken off-air as it is the trp's are low.
Moreover, the characters are still developing.
This is how I see it, The makers had brought Arjun, Sam and Neil to the forfront and established their characters
Arjun came into spotlight for revenge track
Sam as the gal who has a troubled past and is being duped and is in "love"
Neil as the bestie who loves Sam and is also part of the love triangle in a way
Where does Radhika fit in all this, they had to make her come into the equation and get her into all this otherwise she would be another employee like teji, zubin, kritika etc
the only way she could come in was to be friends with Sam and protect her and also be part of the love square pretty soon
so whatever is done is to establish this plot and take it from there