Place the PHP code
if (value('RG01') == 4) {
text(‘IN03’);
}
on whatever page you want the text to appear. If there is nothing else on the page, it will be skipped, if the text is not shown (as long as you did not change that behavior in the questionnaire settings).
Then testing the questionnaire, make sure to start on or visit the page with the random generator RG01 before you go to that PHP code. Otherwise, SoSci Survey will tell you, that no code was drawn from the random generator, yet.
You could also place the rnadom generator on that page (above the PHP code) once more. It's not elegant, but it will still work.