Roseland is the owner of two very distinctive buildings in Gernsbeck: The one with the shiny blue glass facade, in which he likes to show off his treasures to the public, and the grey conical one with the helipads, in which he stores everything that he currently doesn't exhibit. This building is highly guarded, and this is where he and Tessa are in the last panel.
The barrels contain the dragon blood, and the crates contain the Treasure of the Nibelungs (as a little homage to Raiders of the Lost Ark).
This aspect considered, it was a smart move by Starry Wisdom to persuade a third party to store their stuff for them - because in an event of such an attack, their treasures would be destroyed, sure - but not their infrastructure...
because that which can be located can be targeted
and that which can be targeted can be hit
and that which can be hit
can be destroyed
sic semper tyrannis
(Just imagine Roseland attaching a giant plunger to the building...)