How Are You Hiding?

So I have a "cleaning my teeth" routine that goes something like this....

I finish my last food of the day.  I then chew some gum (my theory is it gets things dislodged?) and then I floss and then use an inter dental brush thing and another thing I don't know what to call it, to clean in between my teeth.

Then, either right after or later, I go and brush my teeth.  What gets me is that a lot of the time, when I spit out the toothpaste there is something that got dislodged and I'm like but how?  I chewed, I flossed, where were you hiding?

I mean I guess it's good that I'm (hopefully!?) getting everything but I still wonder sometimes how that little piece of whatever (I'm looking at you lettuce!) stuck out the gum and the floss and the other things.  Like, how?