You can make a timer of your own and call it as you like. Be careful though; test your scripts thoroughly to make sure this doesn't conflict with other scripts that might be running. It will stop the normal processing of some events like ON CONNECT. mIrc does not join your auto join channels until any ON CONNECT scripts are finished.

This Alias accepts time in milliseconds
e.g. ]Wait 1000] will wait for 1 second before returning to the script.

Code:
Remote:
Alias Wait {
  Var %compairTime = $uptime(mirc) + $1
  While ($uptime(mirc) < %compairTime) {
  }
  Return $null
}