Four people suffered smoke inhalation injuries Monday after a Christmas tree caught fire and filled a Chollas Creek apartment complex with smoke. A girl and a woman in her 50s were trapped in their unit at the Regency complex on Home Avenue near Euclid Street when their tree went up in flames. Smoke from the fire filled their unit and billowed out into the apartment hallway before it entered other units, firefighters said. Residents said the fire alarms were going off and causing a panic, but the smoky hallways made it hard to evacuate the two-story building.