Bravo Team

"Marine, Bravo Team is down. Their operational status is unknown."

- Sergeant Kelly, reporting Bravo Team's status to Doomguy after entering the EnPro facility

Bravo Team was a squad of marines stationed on Mars City. When the demons invaded Mars, Bravo Team was one of the few groups of marines to survive the initial wave of the attack. They appeared in Doom 3,  Doom Resurrection and The Lost Mission

Doom 3
Bravo Team's Primary Mission was to "retrieve science personnel and eliminate hostile threats" along with "reaching the central communications tower to send a distress call to Earth's Fleet."

Bravo Team reached Marine HQ (before the player) where Sergeant Thomas Kelly assumed they were the last combat operational fireteam. When he realized the player survived, he commands him to link up with Bravo. Bravo Team meanwhile manages to open their way through Alpha Labs fighting off demons and suffering several casualties as they keep reporting their operational status directly to Sergeant Kelly at his new HQ Center at Delta Labs.

The player spends the first third of the game attempting to meet up with Bravo Team. However, Bravo Team is ambushed by a group of Imps and Wraiths at the Enpro Plant. By the time the player reaches their location, the entire team has been wiped out, save for a single, badly wounded marine.

The surviving marine gives the player a special transmission card that will allow the player to send a distress call to Earth's Fleet. Moments later, the lone survivor is attacked and killed by a Wraith.

The Lost Episode
There was another survivor of Bravo Team, who was merely knocked out during the fights with demons. He wakes up 6+ hours into the incursion and makes his own path through the Mars facility, traveling to Hell, and killing demons along the way. He helped UAC scientist Dr. Richard Meyers in destroying an experimental teleportation array to prevent the demons from using it to invading Earth.

Ultimately he survives and along with Dr. Meyers are rescued by a marine squad from a DarkStar 4409 Dropship.

Doom Resurrection
In an earlier incursion in the same year (June 2145), caused by teleportation experiments gone wrong, an earlier original Bravo Team is wiped out except for one marine. Along the way he meets Dr. Garrett who introduces him to a flying drone robot Sam, who he sends to assist the marine, in an attempt to find a way off the base. He makes his way through overrun sections of the facility including EnPro, Delta Labs, and Alpha Labs, as well as his own trips to Hell where he destroys demonic teleporters before finding a way back to Mars.

On his way through the Alpha Labs, a door begins to close, and Sam selflessly sacrifices herself by jamming the door so he can escape. Before Sam is crushed, she ejects a data card for him to collect. Ultimately he makes it to a hanger, shortly where a group of survivors are waiting to escape in a dropship, and takes the datafile with information on the teleportation experiments in an attempt to expose UAC's unethical experiments.

However, it's noted that his attempt was not successful, and the UAC still managed to cover up the event (referring to it as only a 'regrettable accident', leading to the complete loss of the facility and all personnel) and are planning to rebuild the Mars facility with enhanced safety protocols and foreshadowing the events of Doom 3. Implying that they would be continuing the experiments among others.

Trivia

 * There are two Bravo Team members that have their name given: Sam Lane and John.
 * The team leader of Bravo Team is Sam Lane. His voice can be heard in the cinematic when Bravo Team gets killed. ("This is Lane, give me status.")
 * When the team gets wiped out, two Bravo Team marines do survive: the one that gives the player the transmission card (though he is killed soon after) and the lone survivor from The Lost Mission.

Quotes
"Command HQ, this is Bravo Team. We've got one marine down, two wounded."

"Command HQ, this is Bravo Team. We've got one man down and several wounded. We are incoming and need medical on station, stat!"

"Bravo Team, entry secure. Move in and take positions."

"Quiet! Did you hear that?!"

"This is Lane, give me status."

"Hallway's clear."

"There's nothing here, Sam."

"What the hell?!"

"Son of a bitch!"

"Lane, I'm swinging around left."

"I'm moving in!"

"Man Down!"

"John? Johnny?"

"I'm moving right! Cover me!"

"Watch yourself."

"Fire! Fire!"