I am sorry, but I guess I will have to see more of the sentence. They are separate quotes, so I can only presume as they stand that you would need some sort of conjunction and no extra quotation marks, as for instance:
"Shut up!" "Nightmare."
The main character said, "Shut up" and 'Nightmare."
Thanks. My paragraph currently runs like this (I'm talking about "A Sound of Thunder" by Ray Bradbury): To make the story believable, Bradbury creates rich imagery in the reader’s mind. He achieves this, for example, by using an extended metaphor comparing the T-Rex to some sort of giant machine: “It came on great oiled, striding, resilient legs … examin[ing] men like toys.” He also emphasizes
They are two separate quotes unless they are uttered in the same turn by the same speaker. You don't need the outside quotes at all, but you do need the conjunction and you don't need the colon:
For example, he uses short sentences such as "Shut up!" and "Nightmare."