Several wall segments in the narrow corridors can be destroyed to reveal health kits.
In the large room with the central pillar, check the outer rim for a breakable panel. alien shooter 2 reloaded all secret place
Use a key found in the first medical unit to access a secure area, and look for a hidden room behind a panel after the main defense segment. Mission 3 & 4 (Base Defense): Several wall segments in the narrow corridors can
Follow any corridor that seems to lead nowhere; usually, the back wall is a destructible facade. Mission 3: The Lab alien shooter 2 reloaded all secret place