give red dot an instance variable like vulnarable=false
after you spawn that object put wait 4 seconds action and after that set that variable to true.
only do actions if its variable is true
use the one below if your game glitches, dont remember the object and make all of the red dots instance variable's true
give red dot an instance variable like 4.
every 1 second of game time pick all red dots and reduce their instance varibale by 1 if its not already 0
do actions with red dots only if their instance variable is equal to 0
however you will see from the attached file (just draw something and wait) it perfectly remembers the last created object