Yep, I could not understand the les than 5700 bit either, all 8DC's that I know of are around 7000Kg.
While not likely to be the reason, but I did once see a very ugly hole in the left cockpit side of a Caribou (expecting posts by Tiger any minute now)in Darwin. Made by the Crew Oxy bottle exiting under high pressure and fire.
Followed very closely by the crew.
richo