I reckon she was there to win by playing a character, for example, going on about the talking behind people's backs all the time, she doth protested a little too much me thinks.
I reckon she thought a natural looking, high moral girl who would stand up for herself against the 'bullies' would have it in the bag. Hence her dropping her make up routine and covering up her augmentation once in the house was all part of it. Her sis probably bottled it and that's why she fled.
She then slipped up with the house thinking she was selfish abut her BF staying and in the end she realised there was no point in flogging a dead horse, so legged it and changed tactics going after Marco and the headlines.