Identify and explain Joseph Conrad's formal or informal writing in this passage from The Heart of Darkness, citing specific examples from the text.

"I shook hands with this miracle, and I learned he was the Company's chief accountant, and that all the bookkeeping was done at this station. He had come out for a moment, he said, 'to get a breath of fresh air.' The expression sounded wonderfully odd, with its suggestion of sedentary desk-life. I wouldn't have mentioned the fellow to you at all, only it was from his lips that I first heard the name of the man who is so indissolubly connected with the memories of that time."

It doesn't look informal, but it is. Here's the evidence.

The "miracle" is at first sight an accountant, not one of the disciples. It is a bit inaccurate and exaggerated which formal writing would not do. He came out to get a "breath of fresh air." This is quoted directly from what the man said. A breath of fresh air is not very formal. What did he actually do? He took a break from his work. The writing records a detail that the author is apologetic for. It was an unnecessary detail, but there is a reason for including him. We don't know what it is, but formal writing would never admit to including this. Or if it did use it, there would be no apology. Formal writing is very careful about how quotations are used and for what purpose.