TNG: Brothers
This was the one about both Data and Lore plus the two young brothers where the older one scares his little brother into thinking he shot him and then the younger one runs off and gets sick from eating something, and then needs to be rushed to some starbase or other to get better, but Data's latent programming makes him steal the ship to go back to Dr Soone.
If correct an easy one:
Character 1: "Live long and prosper, so-and-so"
Character 2: " I shall do neither. I have killed my captain, and my friend."