Ah man that's not so bad! Probably didn't help that it was the very first lap and the tires weren't completely warm. I keep hearing the phrase "If you ride, you/re going to fall" and I believe it. I don't go to the track and I don't really ride aggressively and even I have had a few "oops" moments. It happens.
My boring stories (Reading them is optional, seriously kind of boring)
I've set my 250 twice when I owned it, both were at 0MPH. First time, I was turning the bike around on a tiny dead end road. I had done a 4 point reverse/forward maneuver and was almost turned around, but I really needed to make it 5 point, just didn't feel like backing it up the hill again. Instead I thought, "I'll just ride forward, drop the tire off the road down the small 2 inch drop on to the gravel section then pop it back up once the bike is straight and I'll be on my way..." The second the front tire left the road, it dropped off with a bit of speed, I grabbed the front brake, and since the handlebars were facing full left it slid on the rocks and went down out from under me. In the process it managed to flip my shifter around 180 degrees so that it was on top of the foot peg. The shifter was bent in such a way where it would only shift up but not down.
Fun fact: You can actually operate the ninja 250 if you're careful enough, with only 6th gear. Just get a bit of a rolling start, gently feed in the power and slowly let the clutch out. You can fully engage 6th gear at around 25 mph. Which is at 2,400 rpm if I recall correctly that challenge was actually kind of fun.
The only other time I set my bike down I was still pretty new to riding, and if was the first time I took my 250 to the bank drive-thru ATM. I was thinking in my mind, should I do the ATM while still on the bike? or just park the bike and get off? I decided I was just going to get off and stand at the ATM. I rolled up to the ATM, popped the bike into neutral, reached for my wallet with my left hand, went to get off and guide the bike to the kickstand with my right hand but I forgot to put the kick stand down. At a certain point I felt the sense of it should have hit by now, but it was already way leaned over and in motion to go down. I softened the blow as much as possible and it hit the ground gently. Had to get my foot out from under it, then get it back up on the stand. Then it wouldn't start. Flooded the carbs haha so I waited around for about 30 minutes, and tried starting it periodically. Finally it fired and I rode away.