Mat and Edward are still in their trench moving deeper and deeper, trying to see what's around the grave. Maybe there are some other signs of an ancient civilization. That would be pretty awesome.
Nancy and Isabella are busy taking the bones out of the grave, carefully, one by one, when Nancy notices something new. Oh, exciting.
She calls out to Edward and Mat who make their way out of the trench. But, as Mat climbs the ladder, he notices something metal lodged in the dirt wall of the trench. He uses his shovel to dig it out and then finally realizes what it is.
Mat is so terrified that he jumps a little and slips off the rungs of the ladder and falls to the bottom of the trench.
The dirt wall gives way as he falls, too, and Mat is left lying at the bottom of the trench with the metal object—a bomb—hanging over his head.