"Trench warfare is outdated...pitiful." Schmidt was continuing to press up toward the fortress following the progress of the Doombots - they were quite good at their task. Red Skull broke away taking a detour through the trenchworks killing and psychologically breaking Strucker's men in droves putting titanium spikes through chests, nailing some to the walls by their throats and steadily chewing through Wolfgang's defensive lines.
Thinning the enemy was only part of his objective. There was also his real objective - to force Zemo to commit to the battlefield. It would be most unfortunate for the purple masked chemist if Strucker died and left him alone against HYDRA. Reaching a supply depot along the trench lines he set about rigging the building to blow after killing it's guards. To underestimate the Red Skull was to dance on one's own grave.