| Quote #1
He [...] nervously begins to scale the faces of the buildings. (11-13)
The Man-Moth clearly has some level of scruples, since scaling the face of buildings should definitely conjure up some anxiety.
| Quote #2
He trembles, but he must investigate as high as he can climb. (16)
Folks don't usually tremble if they're just a little scared. This is bone-deep terror, and having no choice but to do it isn't helping much.
| Quote #3
he climbs fearfully, thinking that this time he will manage (19)
What is he fearful of here? The task or succeeding at it?