Backup is a game mechanic that allows the player to call for reinforcements to assist in battle. Arrival of Backup will take 20 seconds, and upon arrival, four MCP officers will get out of either a Subaru BRAT, Chevy El Camino, or a Chevy Corvan. One of them will have an M1887 or Remington 870, one will have an M16 or AKS74U, one will have an RPD, and one will have dual TEC-9s. The cooldown time for backup is one minute.
Backup is not available during missions or side missions, due to the fact that most of the time, the player will already be assisted by much more than four allies anyway.
Calling Backup: Brick
- "Will someone please gimme a hand? Thank you!"
- "Where are you guys? I need help!"
- "There's a whole army down here! Help me out!"
Calling Backup: Mad
- "Can I get some help here?"
- "Lend me a hand, will you?"
- "I'm gonna get cut down if I don't get some backup!"
Calling Backup: Rys
- "Requesting backup immediately!"
- "For God's sake, help me out!"
- "It's the whole damn Wikian/IT (Depends on who is shooting at the player.) army! Send backup!"
Answering Backup: Unknown MCP Soldier
- "Hang in there. Help is on the way."
- "Just hang on. We'll be there soon."
- "This is MCP to Brick/Rys/Mad (Depends on who is being controlled by the player.). We copy, over and out."
- "We're on our way. Don't get killed on the way there."
- "Sit tight, we're already out the door."
- "We'll be there faster than you can say 'I hate Wikia'."