An action beat is a stand alone sentence and should be punctuated as such (as well as anything preceding or following it). A dialog tag, however is an injected phrase, and the guidance gets a little weird depending upon whether the dialog is a normal statement versus a question or exclamation.
As the action beat refers to the speaking character, I find that it reads best if it is in the same paragraph as the dialog. I also find that it is better to place the beat at the start (most often) or within a string of dialog. Ending with dialog, instead of with descriptive text, seems to better maintain a back and forth flow of conversation.