How has the experience changed your behavior?
First, some observations.
Sorry, I have used coin-operated car washes before. The time on the wand runs out at the most inopportune times.
To those who suggested the OP get his weapon ready. I did not see where the OP said he was armed.
Did the police really take the situation seriously? I notice there is a palm-print on a freshly cleaned surface. Did they?
Good for you for keeping yourself safe and doing what seems to me to be EXACTLY the right things at the right times under the circumstances. You were vulnerable and took steps to mitigate that condition. Has the experience changed your behavior?
When I first read the title of the thread, I took another meaning of the work "interviewed", that of being questioned by the police, either as a suspect or a witness. Despite the meaning of the word mentioned in the link
http://www.self-defense-mind-body-spirit.com/5-stages-of-violent-crime.html as stage 2 to my mind, what you experienced was being stalked (as in a lone sheep by a pair of wolves). A smart and savvy sheep, though. (edit) Lest anyone take my use of the word "sheep" as insulting, let me be clear. I think you behaved as a Ram to be reckoned with.
Your experience reminded me of what happened to Zarmineh Moody in July 2010 in Yuma, AZ. The Yuma woman was the victim of an attempted armed robbery at the Fry's parking lot on 24th Street and 4th Avenue.
http://www.yumasun.com/articles/moody-61996-purse-knife.html
Your story won't make the newspapers, but demonstrated the better tactics, nonetheless. She was lucky and nervy. You were smart. Thanks for sharing.
Lost Sheep