My interpretation has always been the same as mceachen's, but other comments in this sub-thread have thought me I am wrong and your understanding is correct. Today I learned.

For what it's worth[0]:

> If you do something in anger, you do it in a real or important situation as it is intended to be done, rather than just learning or hearing about it

[0] https://dictionary.cambridge.org/dictionary/english/in-anger