Though if you'd rather not hash out the exact same scenario just with a different ending, you could try a slightly different 'last ones to die' scenario.

In one of humanity's first attempts to colonize the stars, one of the initial colony ships suffered a malfunction and crashed on a barren world. Luna and Meyrin were the only two to survive the crash, and while they've managed to survive in the intact portions of the ship for at least a couple of years in hope of rescue, their supplies are finally running out, the life support is beginning to fail, and the only option left is to end their lives, choosing to hang to death rather than any other alternative.

Meyrin dies first (can be either reluctant or willing), and Luna finds herself aroused when the time comes for her own death, and she feels pleasure one last time as she dies.

That kind of idea work for you?