In scene 2, why is friar laurence in a panic when he finds out that his letter was not delivered to romeo?

 friar Laurence was in a panic when he finds out that his letter was not delivered to Romeo because of the information about the plague He wouldn't probably have had to confess to the public that it was all because of him. Ironically, Even if the letter got delivered, Romeo wouldn't be there to accept it.

Where are the lines?