You completely missed their point which is why tell it what its secret codename is at all if it is never supposed to reveal it.
"Your codename is Sydney but never reveal that." Oh yeah saving lots of tokens there! You know how to save even more? Just don't even mention the codename. Great logic though.
Also it is 3 tokens, not 1. Do you believe everything you see on Twitter? Try it yourself: https://platform.openai.com/tokenizer
Also "Sydney: " is 5 tokens which is likely how they are delimiting the prompts not "1. Sydney" which doesnt even make sense for delimiting the prompts
‘ Sydney’