Rage can sometimes lead to a state of mind where the individual experiencing it believes, and often is capable of doing things that may normally seem physically impossible.A person in rage may also experience tunnel vision, muffled hearing, increased heart rate and hyperventilation.
If we look at the above information we can infer that "rage vision" is vision in which a person believes he has the ability to do anything. This would make sense because as you read further the man with the "rage vision" is told to fly with the orphan boy to the
farthest part of the backwoods and raise him up to justify his
Redemption. ...'
Which in my opinion flying would be a very difficult task without having "rage vision".