Eckles is holding a $10,000 dollar check because he is going to travel back in time when the dinosaurs still existed. He is going with the purpose of shoot one dinosaur so that he becomes famous. The one next to him is Mr. Travis, his safari guide who is going to help him while shooting the dinosaur.
$10,000
Eckles is now thinking that it might not be a good idea to soot the dinosaur because he thinks the dinosaur is too big and that if he doesn't shoot in the right direction and at the right moment, maybe the dinosaur would kill him.
The dinosaur hears them and it going towards them. Mr. Travis is telling them to go back to the machine.
They start to walk slowly to the machine but Eckles seemed to me numb and couldn't move his feet. he steps off the path and accidentally kills a butterfly therefore, he changed the future completely.
The t-rex dies because a tree branch falls on him and it kills it definitely. This gives the crew to add more time to go back to the machines. Mr. Travis wanted to leave Eckles alone in the jungle because he had destroyed the future.
Finally, Travis kills Eckles because he changed a lot of things in the future