I Don't Know How to Feel About This

I'm not sure whether I'm more bothered by the situation itself or by my own (non-)reaction to it...

I get on the metro last night and head to the corner of a car to get a seat. As I sit down, I notice a shoebox sitting on the ground, apparently left behind by some long-gone passenger. No sooner do I see it before I calmly think to myself, "that could be a bomb." I initially chided myself for thinking this so instantly. I do tend to have a very vivid imagination. But the more I consider it, the more odd the old box looks. And it's not necessarily the craziest suspicion to have, considering this, among (too many) other things.
So I mentally weigh whether I am overthinking this shoebox or not. But I am calm. I mean CALM. I honestly put more angst into trying to decide between the McDonalds on Tverskaya or the other McDonalds on Tverskaya. I notice a couple more people eyeing it, but for whatever reason, they decide not to react in any major way beyond a sideways glance. Of course nobody touches it either...
As I am thinking about it an intellectual-looking gentleman in his sixties, across the aisle shifts his gaze from his newspaper to the box on the floor ever so slightly. He, too, appears to be pondering it, his eyes moving several times from his newspaper, to the box, and then back again. Finally he stands, and calmly asks everyone nearby whether this box belongs to them. We all answer negatively and, back straight, newspaper tucked under his arm, he strides calmly to the radio on the otherside of the car to report his find, presumably so the militsiya at the next station can take a look.
I decide to exit the train at this station, as does another couple sitting near us, while the older man waits on the train. As I stand in Mayakovskaya, waiting the two minute interval for the next set of cars, I realise that I still feel nothing but a little bit of hunger and sore feet.
I wonder, did I really believe that there could be a problem after all? I mean, I must have, because I got off the train, didn't I? At the same time, I never once debated mentioning it to someone. Okay, I didn't know about the radios, but even if I had... It seemed to much like panic. Like paranoia. Like the kind of fear you can't really afford to feel at every opportunity. Or to spring onto others unnecessarily.

I have no idea how to feel about this. But I still don't feel nervous.

Of course that in itself is what is unnerving.