When an ambulance passes by, you may pause and give a moment of silence in hopes that the emergency will be taken care of. 
But when it is no longer in sight, do you keep hoping? Or do you just continue your daily life, brushing it off because it is not your business? 
I, myself, am like you.
I show a sign of reverence as soon as I hear the sirens, but play it off like nothing happened when they are out of earshot.
Again, I can hear the screeching bells ripping through the air.
This time, however, the sirens will not go away.
This time, the sirens are for me.