Why Katrina is crying?

Salman and Katrina were shooting together in Abu Dhabi for the last fifty days. The long shooting sequence of 'Tiger Zinda Hai' sequel of 'Ek Tha Tiger', one of the most popular films of their pairs. Katrina Kaif became emotional in the set on last day of shooting. Tears is seen on the eyes of Katrina.

The only buzz in Bollywood is now, Then, with the hand of the picture again came Near Salman - Katrina! At the end of the shoot, Katrina's tears, only for the shooting ended, or the difficulty of going away from Salman?