I had a lot of those moments in my life, but never once have I shat in my pants, instead, I grew to understand that I've got some seriously strong bowel muscles. You see, for some screwed up reason, ever since I was a kid, I noticed that I didn't have what it takes to take a shit in a bathroom other than my bathroom (never pooped outside my house until I turned 18 or so). The thought of me sitting in there in a foreign and unknown bathroom literally disgusted me, I never saw how it could happen. So until I was 16 I worked very hard to make sure that I'd only poop in my own house, where I felt comfortable in my bathroom and at peace.
Now, one day, in my eleventh grade, I suddenly get the urge to take a major dump (diarrhea symptons dump, that liquid poop) while still in school and an hour away from classes being over. Being the kind of student that I was (not good, just not a bad one either) I decided to hang out until class started. I managed alright, with pain and that feeling that I was dying little by little...but then when the bell rang I went outside to see if my ride was there...hoping it was I might add, but it wasn't there, and damn I had no intentions of waiting for it. I couldn't even ask my classmates for a ride since they used to go with the school bus and some used to walk home. I lived 30 minutes away from my school (walking distance) it was a pretty quick decision "I'm gonna walk and take every shortcut I know off".
Granted I made it home in time (booya!) but it was one of the most messed up walk home's I've experienced. I almost got ran over twice, and I felt like it wasn't me walking at all, luckily I didn't get mugged (my city's full of crooks) though I didn't really care, if someone asked for money or whatever I would've given it to them in the quarter of a second just so they could let me walk home and shit. That day I felt like a walking zombie.