He's being tough on her but it's needed because it's for her own safety..
Aaliya is still a child at heart, so if he's not responsible then who will be?
Plus this mission is about protecting a whole nation and it all lies on Aaliya, so one mistake will be costly. If MP is a terrorist then Ranveer needs to take action quickly because MP can do anything at anytime, so unfortunately he can't give Aaliya more time to adjust, because by then it would be too late.
Their relationship is cute though, even though he upsets her he makes it upto her..