I did something similar to this back in the '90s during a fartlek run at night. At some point, I did an all out sprint (as fast as no-speed guy like me can go anyway) to the next light pole and was expecting to need to ease up the effort fairly quickly. But at the light pole, I still felt amazing for some reason, so I kept going all out. I kept thinking I was going to rig, but I kept feeling great, so I kept it up for many, many more light poles than I the one or two I expected originally when I started the hard effort. I have no idea really how fast I was going, or how long I kept it up.
Knowing I was feeling amazing, later in the run, when I went by some known mile marks, I ran a 2 mile effort around 9:30 doing the same thing.
Back when Gerry Lindgren was posting about sprinting and then keeping going during race, that fartlek effort a long time ago came back to mind.