I believe the best thing for Wayne to do would be to wait until he is done with his shift.
Explanation:
In the question, it is said that Wayne is working his midnight shift and that he didn't see any customers coming. Technically, he isn't on break so he shouldn't be on his mobile device. The email may be important, but it can wait.
"I wrote extra r's at the end of roarrr to show the sound the lion made" is the sentence that correctly forms the plural of the letter "r". This is almost always done with apostrophes.