I agree with finding unobtrusive items that you can carry in the office. One thing you might consider is a Mission Wallet -- use it for organizing and carrying small stuff. I carry a Peak Matterhorn Ultra 1xAAA LED, a small Swiss Army knife, ID and a couple $20's in mine.

I don't know which N-95 mask you have, but the medical masks we have here fold flat and would disappear in an inside suit pocket. Having minimal gear in your pockets is always a good thing.

Mindset: This event was a good dry-run, use it as a learning opportunity. Next time you should remember this event and think about your kit. Did you have a subconscious "what am I missing?" feeling before you consciously thought about your kit? You should have a conscious thought about that kit earlier next time.

Fortunately, I traded my briefcase in for a backpack and my oxfords in for cross-trainers years ago. My subconscious would put the backpack over my shoulder before my conscious mind caught up.