"FLASH" is the highest priority for an Emergency Action Message (EAM). According to many amateur radio monitors, it has never been used on the EAM frequencies.
"BREAK" is a controversial work in amateur radio. It should only be used in an emergency and in the form of "BREAK-BREAK EMERGENCY". The crass CB lingo of "Breaker 19" is like fingernails on a chalk board to an experienced radio operator. You might as well begin your rude interruption with "I am a low IQ moron who bought a radio at Wal-Mart and learned how to work it from watching the move 'Convoy'".
Distress signals are either "PAN-PAN" (Possible Assistance Needed" or "MAYDAY-MAYDAY" (Declaration of an Emergency and immediate help required).
"FLASH BREAK" would give an EAM monitor a huge burst of adrenalin and frighten them.