Bruce was not that bold before.
However, Charlie's psychological manipulation was indeed strong. More importantly, Bruce loathed the Rothschild family very much.
The reason why he was able to suppress his hatred and frustration before was entirely because of his fear of the family.
But now, the fear is gone.
Hence, he couldn't care less even though Harrison had called him personally.
On the other end of the line, Harrison was bewildered by Bruce's boldness, but he didn't want to provo