Blade Runner1982

Tyrell:
The facts of life: To make an alteration in the evolvement of an organic life system is fatal. A coding sequence cannot be revised once it's been established.

Roy:
Why not?

Tyrell:
Because by the second day of incubation, any cells that have undergone reversion mutations give rise to revertant colonies like rats leaving a sinking ship; then the ship sinks.

Roy:
What about EMS recombination?

Tyrell:
We've already tried it. Ethyl methane sulfonate is an alkylating agent and a potent mutagen. It created a virus so lethal the subject was dead before he left the table.

Roy:
Then a repressor protein that blocks the operating cells.

Tyrell:
Wouldn't obstruct replication, but it does give rise to an error in replication so that the newly formed DNA strand carries a mutation and you've got a virus again. But this - all of this is academic. You were made as well as we could make you.

Roy:
But not to last.

Tyrell:
The light that burns twice as bright burns half as long, and you have burned so very very brightly, Roy. Look at you. You're the prodigal son. You're quite a prize!

Roy:
I've done questionable things.

Tyrell:
Also extraordinary things. Revel in your time!

Roy:
Nothing the god of biomechanics wouldn't let you in heaven for. [kisses Tyrell and kills him]

Roy:
[to J. F. Sebastian] Sorry, Sebastian. [Sebastian panics] Come. Come.