Why is there a huge gap in the connection between the propane tank to the burner on my grill?

I just bought new burner for my grill, but at the connection from the nozzle, behind the temperature knob, there is a huge gap, I suppose to let air in and mix with the gas on its way to the burner. It looks odd though; its such a big hole in the metal hose... won't the pressurized gas just leak out into the air when I light it up? It looks like my grill is about to become and an incendiary bomb.