Before interior attack operations, which rule of engagement must be met?

• A. One-in/One-out
• B. Three-in/Two-out
• C. Two In/Two Out
• D. No special requirement

Answer: (C)

The safety principle here is having a ready, trained backup outside whenever interior attack is underway. Two firefighters must be outside, prepared to act as a rapid intervention team or rescue crew, while two (or more) are inside working. This two-in/two-out arrangement ensures immediate backup if conditions deteriorate and provides a clear accountability and rescue path, which is essential in interior operations where environments can change rapidly. Without this outside standby, interior firefighters could be trapped without timely support.