The full story
Wade Wilson, out of costume, sees an old man being held up in an alley outside a cinema that's showing Logan. He ducks into a phone booth to change into his Deadpool suit, to a fanfare borrowed from Superman, and takes far too long about it. A shot goes off while he's still getting dressed. When Deadpool finally steps out, the old man is dead and the mugger is gone.
In the version Ryan Reynolds put online the next day, Stan Lee has a cameo.