Quote 1
Kemp suddenly grasped the altered condition of the chase. He stopped, and looked round, panting. "He's close here!" he cried. "Form a line across—" (28.12)
One of the reasons why we're interested in power in this book is because it seems to shift so easily. The Invisible Man is a powerless oppressed student-teacher. Then he's a powerful arsonist. Then he's powerless in the London crowds. Then…well, you get the point. Here, the Invisible Man goes from hunting Kemp (powerful) to being hunted by the people (powerless). Power isn't very stable, it seems.
"Where did you get the money?" asked Kemp, abruptly. (17.89)
Since Griffin is a thief (stealing from his father, from the costume-shop owner, from the vicar), this is a pretty important question.
Quote 3
"He is invisible!" he said. "And it reads like rage growing to mania! The things he may do! The things he may do! And he's upstairs free as the air. What on earth ought I to do?" (18.30)
This is one of the most interesting questions in the book, we think: if you had a friend who seemed potentially dangerous, what would you do? In this case, Kemp decides that he owes more to his neighbors and England than he owes to Griffin, so he decides to help everyone else by betraying Griffin.