I have thought of one way of doing this ,but sure there are a few,more elegant ways...but it should work....
create an invisible sprite call it "timer",give it a variable,lets say "count"
set fade behavior to it..set fade in to 0,wait time to 10,fade out to 0
set it to destroy after fade
when you want to count your 10 seconds....
create sprite "timer"
Sprite "timer" is on created....set variable "count" to score
sprite "Timer" is on screen
score => sprite timer "count"+100.....achievement done!
achievement = not achieved
sprite timer on destroyed.....create object "timer"
I have not tried this,but pretty sure it will work,and you could work it into your events easily.
let me know how you get on with it.