My prediction is that arjun thinks anjali as a big competitor.. Bcz he has climbed many more other mountains and now he is trying Everest... Where as anjali her only aim is Everest...
So when he said she is a drama queen and acting and all.. He must have said the same thing to akarsh, so akarsh being close to anjali must have fought.. And when anjali got to know that they fought over her she got pissed with akarsh!! That's what my gues is...