“Silent Kill” is episode five of season one of Falling Skies.
Tom’s team plan to rescue his son Ben, and the rest of the harnessed children, who are being held by the Skitters at the hospital. To do so safely, they need a method of silently killing the Skitter guarding them so that the Mech isn’t attracted – hence the name of the episode.
Dr. Harris, who had successfully removed a harness in “Prisoner of War”, would have been carrying out the operations to remove the harnesses of the rescued children has managed to get himself killed by the captured Skitter.
The Skitter’s behaviour towards the captured children seems rather odd, especially given that one was happy to execute a whole bunch of them in “Prisoner of War”. Some of Margaret’s past is also revealed.