"Interesting that the uniform of the orchestra is black and white just like a keyboard. And basically a person is auditioning to be a key on the orchestral keyboard."
-Norman Bolter (former 2nd Trombone of the Boston Symphony)
This is why it so imperative to know the excerpts you are playing backwards and forwards. The people who win auditions can play a recording of the entire orchestra in their heads. That includes a number of bars before their excerpt begins and several bars afterwards.
Few people on your committee (if any) will play your instrument. They will be hearing their "key on the orchestral keyboard" while you are playing. If what you are playing does not fit with the part they are hearing in their heads you will be sent home. It is that simple.