You had a slow flat.......air came out slowly. A blow-out sounds like a gunshot and you are completely flat in less than a split second. The tire then starts to come off the rim in about 2 seconds. So you've maybe got a couple of seconds to hit the brakes and unclip so you can throw your feet out to stabilize. Once I was unclipped from my pedals I had to do a "fred flinstone" to keep my bike from hitting the ground. Luckily I wasn't going too fast.......or else my bike and me would have been toast.