Would it be worthwhile for Rybka or Tach to scan the crate for signals? If the commlink's on (and assuming that the box isn't shielded), they ought to be able to hack in without having direct physical access to it, right?
...though I guess, if that were an option, the GM would have mentioned something already.

In addition to the detonating cord mentioned in IC, Hank has a chemistry shop, which presumably would have some acids; I don't think there's anything in the RAW about using an acid to eat through a barrier, so that approach would be very much open to GM interpretation. Does anyone have a tool shop? (specifically thinking of Tach and Marak--Tach to work on its drones, Marak just because he's the big burly type...

)
If we can't come up with something among our characters, I'm afraid we may have to go the contact route, but I'd rather keep things close until we know what we're dealing with. We really don't want word getting to the wrong ears--these guys have already shown that they're pretty serious about this crate.