Take a look @ the next episode of "Arrow", titled "Canary Cry", written by Wendy Mericle, Beth Schwartz and directed by Laura Belsey, airing April 27, 2016 on The CW:
"...in the last episode, with his powers restored, 'Darhk' kills 'Laurel' before escaping with several inmates.
"Then in flashbacks, 'Oliver' helps the island prisoners escape and sets off a bomb to keep 'Reiter' from leaving the tunnels..."
Click the images to enlarge and Sneak Peek "Arrow"...