Discomfort in indifference

I was at the madrassa a few days ago for my usual week-day Quranic exegesis class with the Maulvi. There were two other female students in the class with me (the number of students, aside from me, who sit in on these classes varries considerably). At the end of the class the Maulvi asked if anyone of us had any questions. One of the other women asked the Maulvi what were the consequences if a Muslim in jest and without thinking declared themself to be a non-believer (kafir). The Maulvi thought about this a bit and said that declaring unbelief was tantamount to regecting Islam, and that one would have to formally accept the faith again if they wished to avoid eternal hell-fire. The woman grew visibly distressed at this--she flushed, tears trickled down her cheeks, she began to mumble that she had spoken without thinking, just for fun, and had not realized the enormity of what she'd done. She had clearly been thinking about this for a while and had come to class solely to pose this question to the Maulvi. And now her anguish at the thought that she had somehow rejected her faith, that she had risked being relegated to hell, was palpable.
For those brief moments that I was witness to this ordeal I was suddenly made aware of that great chasm that lay between us. It was not the divide between belief and disbelief, between an unreserved faith in the existence of something and an unerring faith in its non-existence. The chasm was one between faith and indifference. Here was someone who was so vested to her identity as a believer, and so intensely feared the consequences of disbelief...her fear, her repentence, and genuine sorrow at her error were so raw and visible. And here was I, who did not even give these notions the dignity of disbelief. I thought about them in academic terms, as things others believed in, as concepts that moved others, but not me. At a personal level, I care little about acts of faith and disbelief, of how things spiritual and supernatural shape me and my life. How could I care so little about something that meant literally everything to someone else? Never has my indifference towards the sacred left me in a state of such disquiet.