How does the author use foreshadowing to increase suspense in the four paragraph of the story?

The description in Chapter Four initially leads us to believe the lottery is a celebration..... just another party in the town square. 

The lottery was conducted--as were the square dances, the teen club, the Halloween program--by Mr. Summers. who had time and energy to devote to civic activities. He was a round-faced, jovial man and he ran the coal business, and people were sorry for him because he had no children and his wife was a scold. When he arrived in the square, carrying the black wooden box, there was a murmur of conversation among the villagers, and he waved and called. "Little late today, folks." The postmaster, Mr.
Graves, followed him, carrying a three- legged stool, and the stool was put in the center of the square and Mr. Summers set the black box down on it.

None-the-less, the last few sentences of the fourth paragraph foreshadow that we might just be wrong in our assumptions. The villagers keep their distance, illuminating the fact that they aren't really too excited about getting too close to the action. People hesitate when asked for help, thus, we begin to understand that they're not looking forward to what's going to happen next. 

The villagers kept their distance, leaving a space between themselves and the stool. and when Mr. Summers said, "Some of you fellows want to give me a hand?" there was a hesitation before two men. Mr. Martin and his oldest son, Baxter. came forward to hold the box steady on the stool while Mr. Summers stirred up the papers inside it.