Thing type 310, CTF Red Flag, is the flag for the red team in Capture the Flag mode. One member of the blue team needs to collect this Thing and run it back to their base without having the red team take it back. If the red flag makes it to the blue team base (provided that the blue flag is at the blue base), the blue team scores a point.
When holding the flag, players cannot perform their special ability. Getting hurt while holding a flag will result in the flag being dropped. When the flag is dropped, it will stay there for 30 seconds before returning to its base. If a member of the red team picks it up, it returns back to its base immediately, but blue team members can also pick it up again and try to capture it. If a flag falls into a bottomless pit or a sector with the Return Flag sector type, it is automatically returned to its original base.