This isn’t so much of a warm-up as just a general practice. Know your character. The art of theatrical performance isn’t about putting on a mask, it’s about shedding your own and wholeheartedly embracing a new identity. You can tell someone is a good actor when you see none of the actor himself in the performance.
That’s not to say you mustn’t also shed the mask on your character. People don’t want everyone around them to see past the walls they put up everyday, and well-written characters are absolutely no different. Do you think dynamic characters are just completely rewritten, or have they always had that inkling of change hidden within them?
This is just a friendly reminder. Don’t just know your character; understand them.