Answers 1Add Yours
As the narrator, Gene thinks about others' presence of mind for several reasons. First, when Finny suffers his second devastating fall (in Chapter 12, the fall is down a staircase), it is obvious to everyone that he is injured badly. The boys are able to go from being divided over the Gene's "trial" to being able to rally together to get Finny help. Similarly, Dr. Stanpole and the infirmary staff get Finny comfortable fairly quickly and even ask Gene to get Finny's stuff from the room.
These literal examples of presence of mind are important, but what that phrase means to Gene personally is more significant. Throughout his time at Devon, and especially after Finny's first fall, Gene has searched for peace of mind. He tries to figure out why he did what he did to Finny. He worries about whether the other boys know what actually happened at the tree. Because he is looking for his own separate peace, he marvels at others' ability to think on their feet and to do the right thing quickly. To Gene that is the presence of mind that he wants, a mixture confidence and charisma.