I'd be cursing like hell if they came flying out on me.
Sounds like you had an awesome day though.
Bet you was loving it once you got into playing with the mags though.
Just spit-balling here, but maybe you could just put a piece of tape over the hole of the mag with a little flap on it for quick removal?
Once it's fully loaded.
Then just remember to whip it off before putting your mag in your marker?