Gamers often have a casual attitude to death in games. Try throwing some vivid descriptions of death and mutilation at them to shock them out of their complaceny and make the dangers seems realand horrifying.

And if you're not playing Bunnies & Burrows, ramp it up even further.

Transcript

{Jawas carry R2-D2 to sandcrawler and put him in}
[SFX]: < doop bop beedle doodle blip ni-bing >
[SFX]: < fip-jing boodle pip-jing bang >
[SFX]: < doop whiddle e-pok whir bang boop fip-jing >
[SFX]: < doop buzz bebepok squee boo-diki ooyoo >
GM: Delivered to this dark, dank den of despair, you discern a disarray of disheartened, disfigured, and dismembered droids.
R2-D2: You've been practising that sentence, haven't you?
GM: Definitely.
GM: Amidst this scene of charnel horror you see a familiar figure.
C-3PO: I'm not talking to you.
R2-D2: Darn.