Marsh & Clark Design interview questions

Applied online. Started with a phone interview. Interviewer sounded really nice over the phone, and after a while she invited me to "shadow" in the office for a few hours a day to see how we would work together, ie work for free. I stupidly said yes and went in, and did actual work like update a skechup model. The office environment was a home-adjacent office in a garage. In the few hours I was there, I heard her lose her temper to a staff member and got a weird/tense vibe from the office. She never replied me after I left; didn't even have the courtesy to thank me for coming in working for her for free a few hours. This was in 2014, but I doubt people change, and I still want to share my experience.