Obviously not a problem for IFT6 since it's sub-orbital, but the original comment was about why we need a deorbit burn rather than just triggering the flight abort system.
No. In LEO orbits degrade in single-digit years at most. There is no known solution for rendering an orbit in LEO inaccessible with a Kessler cascade—the best you can do is blind an area with repeated ASAT fire.
In higher orbits debris last longer. That makes cascades possible, though again it only denies a limited area and requires almost active effort.
If you have debris in geostationary orbit, it will stay there basically forever whereas in low earth orbit it will burn up within a few years at worst.