I've had enough people PM me to say "don't be an idiot, you have to tailor your responses to the job being offered, e.g. if the job is all-filing-all-the-time then you say I filed this, and this, and then my supervisor gave me more things to file!"
I know that. ^__^
The mock interview wasn't, at least to my understanding, for any particular type of position.
Which is probably where I went wrong in the first place. When the agent said "we're going to run a mock interview," I should have responded with "what's the position I'm testing my interview strategies on?"