I have to fully agree here. When I have my team doing HIIT, it's never on a treadmill as it takes way to long for the machine to respond to something your body can do in a fraction of a second.
If you have issues such a shin splits and that's preventing you from running outside, then try to find some good trails near where you live. Heck, even in the core of a city you can find a good field to do your HIIT.
Also with your intense portion going 3 minutes, it's turning into steady-state cardio. Switch to a 30/30 program, where you have 30 seconds walking and 30 seconds intense sprinting.