The narrator's perception of the worst part of his circumstance is captured in the second underlined sentence.
Why do you think that, the narrator?
Because he indicates to the reader that things are about to become worse by adding "but this was not all" after describing a painful incident.
mostly because the narrator finds his connection with his staff to be so uncomfortable.
The phrase "but this was not all" can let the reader know which scenarios the narrator thinks are the worst. This is due to the narrator's usage of the phrase "but this was not all" before describing another unpleasant event in his life.
The expression here indicates that although though the first moment was really uncomfortable, it wasn't worse than the second, which was more severe and made the entire situation appear worse.
In this instance, understanding the narrator's grammar was crucial to understanding the material correctly.
