Both Miracle-Mineral-Supplement and Hydrogen Peroxide are oxidative therapies. Both cause oxidative stress on our bodies and pathogens in our bodies. To an extent we can deal with oxidative stress better than most pathogens.
That said, though they work slightly differently, the two together will most probably increase the oxidative stress you are placing on your body. As a result I see no real advantage to using both concurrently.
If you do try both concurrently please report back on your experience.