No stage fright?
Stage fright is the sudden fear and anxiety one has before performing onstage before an audience.
Burn the bridge?
Or they’re advising you not to be half-hearted. Perhaps this is a better explanation.
Game face?
To have your game face on is to start taking the job at hand seriously.
Child in a candy store?
It's a feeling that you have everything you want in the world all to yourself.
Blame the brass?
Top brass means officials at the very top. The brass stands for the company's bosses as a group.
Tall task
A tall task is something difficult of accomplishment, if not entirely impossible.
Eat the cake and still have it?
It means you can't have the action and not have its consequences as well.