In A Sound of Thunder, written by Ray Bradbury, Eckels pays to travel into the past by using a time machine. In paragraph 3, the reader can already get a glimpse into his character, which I am going to explain further now.

At the beginning of the story, we see Eckels in the office of a company, which is offering time travel safaris, as revealed by the sign that says “TIME SAFARI, INC. SAFARIS TO ANY YEAR IN THE PAST.” Eckels is looking at this sign and clearly gets excited by it, as he is looking forward to the adventure he is going to embark on. However, he simultaneously seems to be a bit nervous, which is why “warm phlegm gathered in Eckels’ throat.” He is trying to not show this nervousness, therefore handing over the money whilst “the muscles around his mouth formed a smile.”

In order to ease his nerves, Eckels needs confirmation that his adventure is not going to be dangerous, as he asks whether “this safari guarantee(s) that (he) come(s) back alive,” which shows that he is not 100% confident about this safari. This could indeed be seen as an early indication of and hint towards the actual outcome of the story later.