Have a condition.
In your alarm trigger put this is the activation bit,
Alerted = true
In your flare trap have in the condition field,
Alerted
That way when the alarm goes off, Alerted will become true.
The flare trap is waiting for Alerted to become true. When it does, with the alarm trigger, the flare trigger's on activation will start.
The Alerted bit can be anything. WhooshFlare or KaBoink. Anything.