You should tell people before you leave somewhere.
Kendra goes to the mall with her friend, and they are shopping at different stores.
Kendra wants to leave the mall.
Kendra finds her friend and tells her she's leaving before heading home.
Kendra leaves the mall without saying anything to her friend and goes home.
Kendra's friend keeps shopping at the mall in a carefree manner.
Kendra's friend spends time looking around for Kendra and starts to worry about where Kendra is.