“Death Knell” is episode sixteen of season seven of Stargate SG-1.
Sam and Jacob are working at the new Alpha Site – the location was changed after the gate address of the previous site was discovered by Anubis – on a weapon intended to destroy Anubis’s new super soldiers encountered in “Evolution: Part 1” using the Ancient device discovered by Daniel and Dr Lee in “Evolution: Part 2”. The base is suddenly attacked by Anubis’s forces – presumably, the location has been compromised again somehow; seems rather poor operational security – and the self destruct is activated. Jacob is discovered, injured, but Sam is missing.
Teal’c and O’Neill go looking for Sam, who is probably being followed by one of the drones, whilst General Hammond tries to find out how the location of the base was compromised. The prototype weapon is not entirely functional, but Sam apparently has a power source that can upgrade it. Jacob thinks the base, and he and Sam, were specifically targeted for the prototype.
Fortunately for Sam the drone is a proud graduate of the Imperial Stormtrooper Marksmanship Academy.