Perhaps, I said doubtfully, for I was really quite indifferent to the fate of Alfred Inglethorp, and thought that a good fright would do him no harm. 
Maybe, I said regretfully, for I was greatly concerned about the fate of Alfred Inglethorp and worried that too good a scare would harm him.
mnli hypothesis: Maybe, I said regretfully, for I was greatly concerned about the fate of Alfred Inglethorp and worried that too good a scare would harm him. premise: Perhaps, I said doubtfully, for I was really quite indifferent to the fate of Alfred Inglethorp, and thought that a good fright would do him no harm. 