I love when u said "there's only one place to open these!" TO THE CAR! I noticed a trend with you: anytime the secret/mystery one is on the box you tell "I'm not getting more!" since the odds are so low. Like 1 in 60 boxes something?
Yup lol imo it's not worth it to keep trying to open more blind boxes/packs for the mystery one. It'd be better to buy it off straight from someone else (if you manage to find one ofc) as you're guaranteed to get it even though it'll be more expensive than one blind box, but surely NOT as expensive as trying your luck at finding it yourself by buying more lol