1. Star Trek: The Next Generation “The Best of Both Worlds, part 1” (end of season 3)
Jean-Luc Picard captured and converted into a Borg. Borg en-route to assimilate Earth. Will Riker confronts his captain and says the words “Mr Worf – fire.”
“If you go to Z’ha’dum, you will die”… just as the audience has completely invested in the character of John Sheridan and the series has really gotten into its stride… Sheridan jumps into the abyss and the thermal fusion weapon-filled White Star crashes into the planet. 3. Dr Who, The Stolen Earth (penultimate episode of “new” season 4)
Universe about to end. Davros resurrected. Earth stolen into a space/time pocket. Daleks everywhere. Realities collapsing. The Doctor and Rose about to reunite… the Doctor is hit by a Dalek’s extermination ray… collapses in the TARDIS and starts to regenerate.