[@Mega Birb] Syphax does not have any means by which he can bypass Alexi's power, until when it stops because there is a hole in space where her torso used to be. See below. You literally cannot intervene unless you've got more powers up your sleeve then are on your bio.

Inviolability of the Mountain Peak- This creates an aura which places a "maximum speed" on all physical objects within a short distance of Alexi. Bullets become dodgeable, allowing martial combatants with the skill to parry arrows the potential to parry bullets. Momentum is however left intact, because magic says so, so the objects become no less deadly. If something enters then exits, it resumes appropriate speed.