Ensign Ahni Jetal was a junior officer on the USS Voyager during its time in the Delta Quadrant. She was popular and well-liked among the crew; she was even friends with the senior staff. On her birthday, many of the senior officers organized a surprise party for her in the mess hall.
In 2373, she was piloting a shuttle on an away mission with Harry Kim when they were attacked. The alien attack injured both her and Kim with a residual energy charge, which had implanted an energy pulse that resided in her neural membranes. The ship then came and attacked Voyager as the pulse moved up her spinal cord and into her brain, resulting in death by massive synaptic failure. With no time to treat both patients, The Doctor was forced to choose to treat one of them over the other, and he picked Kim simply because he knew Kim better. This choice, however, resulted in Jetal's death.
Her death later caused a contradiction in the EMH's programming due to the ethical issues involved in him 'choosing' to kill one person over another simply because of a personal connection rather than making the decision based on which patient had the better chance of survival. This resulted in Janeway ordering that The Doctor's memory of the event and his knowledge of Jetal should be erased. However, when the memories resurfaced again in 2375 after The Doctor discovered evidence of the surgery he had performed on Kim, a conversation with Seven of Nine prompted Janeway to decide to let The Doctor deal with the memories and try to work them out for himself, acknowledging that they couldn't help The Doctor become a person only to treat him as a machine when it was easier. (VOY: "Latent Image")