Recalling the story of the Chinese Briefcases on BEZERK, there was a claim that if the briefcases were opened before the designated time, that the contents would be destroyed.

The Chinese are expert in manufacturing a thick, heavy tempered glass that is supposed to be heat resistant, but which can blow up like a roadside bomb blowing shrapnel around the immediate area. All it appears to take to detonate the glass bomb is a sudden change in temperature. If a message is engraved on a glass canister, or on something breakable inside a glass canister and a timed heating device is packed with the glass canister, an early opening and exposure to ambient temperature could possibly cause the destruction of the message.