Gort
Klaatu has been shot upon his initial arrival on earth. Gort then appears, and this figure frightens the mass of people. He then destroys their guns and tank with his laser. The imagery reveals that, even with the most technologically advanced weapons, the people of earth stand no chance against Gort.
Trigger Happy
We watch as a soldier shoots the object that Klaatu opens out of his hand, injuring the alien. The imagery, which presents the soldier in a medium shot, reveals the fear which he is operating from. This image shows that the soldiers are responding out of fear rather than out of knowledge.
Pinned
Helen goes to Gort and we watch as she is backed into a corner and falls down as the giant shadow of Gort comes over her. The imagery shows us that this is a final moment for her; she will either stop Gort or he will kill her.
Last Chance
Klaatu speaks to the assembly of scientists at the end of the film. We see them in close ups as he speaks of freedom and the reality of peace and their destruction if it isn't accepted by humans. The imagery speaks to the idea of this film: that without peace we will all perish.