Woah!! This really is a good representation of Russian roulette as a Twine game! Very well done! Few things I was thinking of -
1. Russian roulette (or depictions of it) relies on suspense. I think the element of suspense was present but I wish it was reinforced. Perhaps the quickness with which the result of the action takes place reduces the suspense a little.
2. I love the option of running away, almost a cop out from playing. Throws the user in a question of "wow I can't play a roulette even when there is no physical consequences to me"
3. The way you coded the elements of chance, on what the roll would be, so so wonderful! Sometimes I would die straightaway, and some times I would survive till the last bullet, truly a wonderful $variable showcase!