> The
>    test="c02[...]"
> is true if there is at least one such c02 so you seem to want
>    test="every $c in c02[not(@level)] satisfies (every $i in 
> $c/did satisfies $i/container)"
> to ensure all c02 satisfy the condition.
> 

which can also be written

test="not( c02 [not(@level)] [not( did [not(container)] )] )"

though I admit it needs a clear head to read that (and I might have got it
wrong...)

("if there is no c02 with no @level that has no did without a container..."

Regards,

Michael Kay
http://www.saxonica.com/
http://twitter.com/michaelhkay