How to execute a function for "t" time without delay + using external interrupt

Using Arduino Project Guidance
4

Easy:

void run_me(void) {
  static unsigned char execution_count=0; //execution counter

  if (++execution_counter > MAX_RUN) return; //if total number of runs exceed, do nothing

  //put your code here
}

All you need to do is to specify MAX_RUN.