Friar Lawrance gave Juliet the potion that was going to make her fall into a death-like sleep.
Juliet gave Friar a letter addresed to Romeo explaining the fake death plan
YOU ARE NOW LEAVING VERONA
So, Friar Laurence ran to Mantua with Juliet's letter
You are now leaving Verona Come back very soon
Friar Laurance successfully made it to Romeo. He gave him the letter.
My Dearest Romeo, It has been too long since we crossed paths. I am with my cousin and angels till the second sunrise. Come by my family tomb where I may be. We can run off to Mantua together, my little nightengale. Your love, Juliet
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Juliet, by and by I come my sweet Juliet!
z z z
Romeo ran from Mantua to his beloved Juliet, who awaited his arrival in her family tomb.