Watching somebody's head explode will not invoke fear. Security robots are armed with lasers powerful enough to explode a person's head. Pillows can explode. Security robots are armed with C4. Safe air ducts are extremely frightening.
Robots have blood.
Robots can read our minds. Molotov cocktails are extremely ineffective when used against fast moving robots. Security robots are armed with cutting torches. Marine training is inherited through genes. It's always a better idea to run around a mall with killer robots than to stay hiding where it is safe.