Why did Swarn leave his friend Mohan in the waters ?

Directions: Read the passage and answer the following question:

It was Sunday. As usual, there was a great rush of merry makers who had come to the river to swim or to bathe. Those who knew how to swim were jumping into the water from the high bridge or the banks of the deep river. Mohan did not know how to swim so he was merely watching others who were enjoying the fun of swimming. However on the insistence of his friend Swarn, he sat on his shoulders and both jumped into the water. Unable to carry Mohan along, Swarn left him in the flowing water. Mohan shouted for help. There were so many swimmers but nobody came to his rescue since they were indifferent to the plight of a stranger. I had just reached there, so I was in my full dress. Without undressing I jumped into the river and swam up to the drowning boy. Holding his left arm, I brought him out of water in a way that he might not hinder me from swimming safely. The boy was saved which won me great applause from the people. I had jumped into the water without any fear or hesitation as I knew the art of saving drowning persons. I had already saved a few lives from drowning.