Elise is also the lover of fellow astronaut and participant Angela Olvera, with the other participants including Tom Hammond, Mikhail Dankov, and Rusham Haroun. The rest of the group found out that Mikhail was selling the mission's secrets to a rival group funded by Sir Ian Rasher; plus they were highly annoyed with Tom after spending six months with him.
With that, Elise colluded with Angela and Haroun in a plot to kill Tom and set up Mikhail in the murder. As part of the plan, the evil Elise sent Mikhail to engineering, after which she and her cohorts convinced MIRA (their mission computer) to believe that Tom was a threat to their mission. As a result, the rover, which was connected to MIRA, grabbed Tom's screwdriver and stabbed Tom to death, with Angela and Haroun ditching the weapon afterwards. Mikhail, however, took a photo (among others) of the rover with the murder weapon, and that led to Castle and Beckett--along with Viggo Jansen--to attempt to get information out of MIRA. Their attempt led to the trio being locked in the room and nearly being killed by a gas attack, while MIRA's memory chips were destroyed.
Castle and Beckett later figured out that Elise, Angela, and Haroun colluded together to kill Tom and set up Mikhail, with Elise arrogantly responding that they had no proof. The pair later stated that MIRA had a black box that would send any of their conversations to a satellite, meaning that their plan to kill Tom would be revealed. The "black box" was a ruse cooked up by Castle, but not wanting to take any chances, the conspirators caved and confessed, leading to their off-screen arrest.