Is the clerk the one who sent the group back in time?

So the clerk in the store, he says "ok, I'll open the safe but you might not have the stomach for what's inside." So is the clerk the one giving people second chances to go back in time and change things in their lives? Because when the 1984 girl (I don't remember their names) demanded the clerk to open the safe, the clerk said the same thing and then poof! The 1984 girl got sent back in time and then at the end of the film, the next "bad girl" demanded the same thing - for the clerk to open the safe and the clerk said the same thing, so will this new "bad girl" be going back in time too? I mean, is this clerk the one sending people back in time?