Heroic Ragnaros Phase 4 question

[Shazzia]

Hey!
Our guild (10) just got 3 wipes below 3% (fml) and I'm the one extinguishing the fires. But at some point I notice the fire spawn like shit crazy wat! Is this triggered by time or % on ragnaros? Should I stop going into fires at some point and concentrate on dps?

[thehordemage]

every set of dreadflames spawn 5 seconds earlier than the previous set, starting at a 40 second timer, with a cap at 10 seconds.
40->35->30->25->20->15->10->10->10. stopping and dpsing at any point is your call depending on your raid dps