Why does Juror #8 dismiss the phrase "I'm gonna kill you"?

9th Juror identifies with the poor old man, believing that he might just be trying to feel important. 8th Juror concludes by saying that even if he did hear him say, “I’m gonna kill you,” that very well could be taken out of context as just a figure of speech. With this 5th Juror changes his vote to “not guilty,” and the vote is 9-3 in favor of guilty.