I think the past episodes can help us a lot in figuring out Prem's motive behind hiding the truth. He says stuff like "zindagi tab mushkil bhari hoti hai, jab dard kai ehsaas ka ehsaas bhi nahi rehta... har dard mehsoos hona khatam ho jai and FINALLY zindagi mushkil bhari tab hoti hai jab Insaan key andar ka Insaan mar jaye"
Clearly he's telling his own life story after the bomb blast.
What are your inputs?
Here's the link to the video if you haven't seen it:-