I Think I Have Some Idea

Nathan was on edge when they finally did have to stop for gas. Especially since there was a fast-food restaurant attached that Sierra wanted to eat lunch at, which would only keep them there longer. 

He ate his cheap tacos apprehensively, on the lookout for something going wrong. Nothing happened while they were eating and he was beyond ready to leave once they both used the restroom but she wanted to buy some snacks for the road since they weren't planning on stopping again until they got to their hotel. 

Of course, something went wrong. It wasn't what he expected though. The aisle they were standing in suddenly exploded and every single product in it violently flew off the shelf though the shelves themselves were untouched. What on earth?