Only a Flesh Wound: Averted. Sure, modern transsophs have all kinds of enhancements for durability and healing – smart cardiovascular nets, auxiliary hearts, better blood clotting, etc., etc. Those will help you if something slips past equally modern milspec combat armor with full kinetic barriers, or against a (very) glancing hit or ricochet, or against car wrecks, or shrapnel, or stabbing, or being on the fringe of an explosion.
But a mass-driver gun tosses target-customized flechettes downrange at appalling, air-plasmating, entirely excessive velocities. If you get hit directly by one of those without armor, or with enough of them to overcome its protection, it’s a bone-pulverizing, flesh-pulping experience that is almost certainly not survivable – and there’s no safe place to be hit.
If they bring up the heavy weapons or go to full-auto, it’s all over bar picking the vector stacks out of the slightly-charred chunky-salsa-esque ooze.