Although you could also accomplish this through the use of User Macros
/s Staring in 5 <wait.1>
/s ...4 <wait.1>
/s ...3 <wait.1>
/s ...2 <wait.1>
/s ...1 <wait.1>
/s ...GO!!!

also consider changing /s to /p then you can also use sound effects <se.1> etc