It brings me to question whether or not Mass Gain/Shed tech changes the density of things like armor.
It could be that her armor retains all the protection it normally would but adding mass through mass gain tech would enable you to brush off the kinetic energy of a blow while Light Mode would send you flying.
In Light mode the armor would have no protection against the kinetic energy the bolt had from the velocity it was traveling. Only in Heavy mode would it have the mass necessary to prevent penetration.
Panel three does well to show a kinetic transfer. Actually, its a nifty concept for armor being shown there. Normally, kinetic impact of one substance on another would generate a short flash from spalling. The depiction in panel three would indicate energetic discharge. Now there's really only one armor concept that could remotely both fragment (as opposed to deform which would indicate monomolecular armor) and produce an energetic discharge (which indicates what is intended to be artificially reenforced inter-atomic bonds) and that's the theoretical energized polyhedral lattice. Current physical and material science can use the material as a exceptionally efficient battery because of this high interior and exterior surface area and a very very good medium for affecting and controlling magnetic fields over irregular surfaces within the lattice (prohibitively expensive though). The material easily fits cannon for creating localized changes to physics.
Additionally, its pretty to look at.
It's called "fluttering" in-universe: the impact warps the mass shed membrane slightly, which means there are "mass ripples" vibrating out from the point of impact at the speed of light.
You can do all sorts of fun stuff combining that with mass-reactive alloys, atomic bonds, and even just exterior glazing.
Re-reading this page just makes me think about how interesting it would feel, and how much practice it would take, to grab a very heavy object (like a body in powered armor) while you're nearly mass-less. I just want to play with their armor now :<