Thief attacking a Lawyer

[mawile]

When a Thief meets a Lawyer, is he fast enough to discard his class and attack a Lawyer, or Lawyer is faster and he is discarded asap?
(also a similar question with an Amazon and fast playing a sex changing curse and any other such non-attacking monster)
afaik, i can discard classes (or play curses) at any time, so that's why the question.
I found two contradicting messages on this topic, so I wanted a small clarification. This allows you to discard a class in order to attack. And here Andrew tells to discard a monster, but he is not answering my exact question, so i'm not sure.

[MunchkinMan]

Since Zonderion is neither me nor Andrew, why even consider it a correct and official answer? It's an immediate effect, so you can't fight the Monsters in those specific situations.

[mawile]

i'm not considering it a correct answer. i won't ask, if I did:) but Andrew's answer was not for this specific situation, so i wanted to make sure. Thank you so much, MunchkinMan.