Two km, working for speed

It was a sweltering 20° at 9:15, and I am trying to improve my speed.

Started running at a purely impossible pace, which I kept up for 60 seconds, then slowed to my normal pace for the next 120. Alternated this way to the 2 km mark (jogging an extra 20 seconds at the end) to achieve a time of 6:21. Walked for two minutes before turning around, then alternated one minute of fast with one minute of walking, till the end when I ran two minutes, then walked the very last one to the apartment and came in at an elapsed time of 15:24 (only 13:24 of which was on the distance, though).