Actually, always have your camera on silent mode when shooting mimes. Kaiw74 is right about improvisation making it memorable, so stay alert for those breaks in character. You'll miss the genuine moments if you're fiddling with settings.

Consider the mental discipline required for that month of zone 2. Did you use any tricks to stay slow, or did you just white-knuckle it? I've tried similar phases and always end up checking my watch every five minutes, convinced I'm wasting my time. Hearing that your times dropped afterwards is the only thing that makes it bearable. What was the biggest surprise when you reintroduced speed work?