Fast running is hugely important and this session is all about fast running. Do the 400m at well above your 5k race pace, so that at the end of each 400 you feel you could go on but are happy to be stopping. Then run the 200m even faster than that, again being happy to stop after the 200m.
Running swiftly has a few benefits, your footfall is often better, the neural pathways learn to run faster, your mind gets used to the effort necessary and your mitocondrea building and aerobic enzyme uptake occurs quicker than at slower speeds.
Warm up well before you start the fast sets and stretch if you need to after the warm up.