Greene

Captain Greene was commander of the UNSC Apocalypso, a Prowler in the I Love Bees storyline. While on their mission, the ship picked Covenant transmissions about attacking the UNSC colony Troy. Greene was forced to make a decision to either give forewarning to the colony allowing them to evacuate and tip off the Covenant that thier communication codes have been broken, or let the Covenant attack thus maintaining the ability to listen to Covenant communications.

Her decision is played through Melissa (A.I)'s eyes in the flashback scenes when the SDPR is rebuilding Melissa and can be read in the Phase 2 Operator's Monologue. The following conversation was observed by Melissa between First Lieutenant Rolf Sorenson and Captain Greene.

Part of the Phase 2 Operator's Monologue
Ist Lt Sorenson: Oh my God. If the decrypt is right- Capt. Greene: I know.  1st Lt Sorenson: We have to /// drop the mission.... An evac on this scale they need every second. ...Jesus. Capt. Greene: I'm not... I'm not sure. 1st Lt Sorenson: The mission... This mission is more important than millions of lives? Oh my... /// god. Capt. Greene: I'm just saying, the choice isn't as easy as you might think. Capt. Greene: ...If they act, they risk letting the enemy know we have a toehold in their /// C-and-C. If they decide that strategic advantage is too great to risk and don't act, then you know Section Zero will be all over them. Zero's wanted Standish forever. 1st Lt Sorenson: I...I understand. It's so much easier for everyone if we don't tell them. But...wait a second. Don't you have family on Troy? Capt. Greene: That can't be part of the equation, Rolf. You know that. 1st Lt Sorenson: Jesus.

As shown Captain Greene was forced to make the strategic deicion and risk not saving her family on the doomed colony.

The Covenant did suspect that their transmissions were being bugged and included a Covenant A.I. acting like a Trojan Horse to any evesdropper. The Apocalypso and Melissa were infected. Captain Greene was the first that Melissa told and the she decided to head home to check things fully but before they did scanners detected an Forerunner Artifact This is also shown in the Phase 3 Memories flashbacks

Even though Greene didn't want anyone tampering with the mysterious cylinder they found adrift in space but the Covenant A.I. tricked one of the crew to tamper triggering a huge explosion that fragmented the Melissa A.I. sending parts back in time.

The ship managed to limp back to Earth and when it arrived ONI Standish seized the artifact and hid it's existence from his superiors. Another ONI agent, Herzog suspected that Standish was up to something and through transmissions from Durga (Another fragment of Melissa that didn't get sent back in time) we learn that Standish killed Captain Greene in an effort to coverup the existence of the artifact. "Some accident involving a bus. Unluckiest thing in the world."