Doing player actions on world tick

I'm making a procedure that runs on world tick update. I want the procedure to send a message to all admins on the server when something happens; so I have the block "For each player in the current world" along with an "if player has permission level". The problem is that MCreator complains that there is no provided player dependency when using the world tick update. I would assume that the "for each player in the current world" block provides that to the blocks contained inside it; but apparently not. Is there not a way around this? 

I could conceivably run the procedure on player tick update instead; but I'm not clear on what the difference between the two is. If I run the procedure on player tick; does that mean the procedure is run multiple times for every player on the server?