locked wooden cupboard. can't unlock it.
break into it
mountain. don't go over it, don't go round it.
go through it
(if the eruv food is in a locked cupboard, if the cupboard is wooden then it could be dismantled/broken into. as it can be considered as not a 'structure' but a 'utensil.' and when measuring distances to determine the Shabbat boundary, then measure as if can pierce through a mountain)