To save the wall if your on the Galactic Republic, you must use the Clone Engineer to fix the wooden barricade (This is, of course, in Star Wars: Battlefront II). You must be on the Galactic Republic side and either get on the big turrets or become a Clone Heavy Trooper. There is a gigantic chance that there will be a steady flow of Armoured Tank Droids and STAP swarms. Not much risk but the Shock Cannon fire is a thing to be careful of.