What does Eckels do that irritates Travis just before they see the dinosaur?

Just before they see the dinosaur, Eckels irritates Travis by continually questioning the safety of the environment and the rules of time travel. He shows a lack of seriousness and respect for the mission, which frustrates Travis, who is trying to maintain focus and emphasize the importance of following the established guidelines. Eckels' nervousness and nonchalant attitude further exacerbate Travis's irritation.