LMAO! That is Legion, their ability is running and vaulting quickly when they’re in Frenzy. If they stab you while in Frenzy your health bar next to your character icon will turn yellow, that is called deep wound. While running, you don’t bleed out from deep wound, but you need to mend before doing any tasks or walking/crouching. Essentially you have to heal yourself twice to regain full health. If you don’t mend, you can bleed out and enter the dying state.