The swarm of crazed people was rushing toward them. Mac turned the keys in the truck's ignition. The engine sputtered but refused to turn on. "Try again," said Dennis. Mac turned the keys again. Again the engine coughed, and the emergency lights flickered before it cut out. Mac tried to stay calm, but he felt a wave of cold panic.

"Keep trying the engine," said Dennis. "I'll hop out and try to push the truck to start."
Dennis jumped out of the truck and ran to the back. He shoved the truck's bumper, pushing all of his weight against the vehicle. Inside the truck, Mac kept turning the key in the ignition. Dennis could hear the angry roar of the mob as they grew closer. Dennis gave one final push and felt the truck move. He scrambled into the truck's bed. "Go, go, go!" he screamed at Mac.

What do you infer?

The group of people rushing towards Mac and Dennis are described as crazed, which suggests they are behaving aggressively or irrationally. The fact that the truck's engine doesn't start adds to the tension of the situation because it puts Mac and Dennis in a vulnerable position. Dennis suggests that he can push start the truck while Mac keeps trying to start the engine. The urgency of the situation is heightened by the approaching mob and Dennis' desperate pleas for Mac to get the truck moving. Overall, the passage creates a sense of danger and suspense as the characters try to escape the oncoming threat.