What can't the travel agent guarantee in "A Sound of Thunder"?

When Eckels initially enters the Time Safari office, he experiences fear and anxiety as he raises his hand in the air to ask a question. When Eckels asks if the safari company guarantees that he will make it back alive, the official responds by telling him, "We guarantee nothing . . . except the dinosaurs" (Bradbury, 1). The safari official's statement suggests that the Time Safari is a dangerous expedition, and the company cannot guarantee the hunters' safety, which is unnerving and contributes to the suspense of the story. The official proceeds to introduce a Safari guide named Travis to the first-time hunters and warns them that there is a ten thousand dollar penalty for disobeying Travis's orders. Eckels and the other hunters are then required to sign a release form that states that if anything happens to them during the expedition, the company is not responsible. The fact that the company cannot guarantee the hunters' safety and requires them to sign a release form builds suspense and foreshadows Eckels's dangerous, life-threatening experience.