Screen Shake Not Starting

I have a cutscene where two of the antagonists cause a cave-in to block the party's path. I would like the screen to shake through the preceding dialogue before the ceiling collapses and the path is obstructed. The problem is however, the screen-shaking will not start. (It works when placed into the event with all the dialogue, but I can't use it in a loop if it's part of that event.) Here's a couple of images of the common event I'm using and the event that's supposed to trigger it:

Can someone tell me what's going on?

EDIT: I discovered that the shaking does indeed start, but it starts after all the dialogue has finished. Why is it doing this?

Amazing what you can find by typing Screen Shake into the search box ;)


http://forums.rpgmakerweb.com/index.php?/topic/16754-how-to-make-screen-shake-continuously/

I saw that topic before coming here, I already know how to make the screen shake continuously, my problem is that the shaking doesn't start when it's supposed to.

EDIT: I got it to work by adding a 10-frame wait event between the "switch ON" and the dialogue. Huh, weird.

I believe the "reason" for this is that the game tries to process certain event commands as a "set" before actually processing the results onscreen.  But using the "Wait" command forces it to stop trying to process things in the event until the Wait completes.  So whenever an event doesn't work as I expect it to, I try adding short Waits between certain lines and sometimes that does the trick.  Whenever the event includes "Script..." commands that seem to be handled too quickly as a "set", I also try changing the value of a dummy variable that isn't actually utilized in the game.  For some reason, sometimes that makes the event/scripting process correctly.