What circumstances in the play, R and J, force Friar Lawrence to make a desperate plan to help Romeo and Juliet to escape together? How does...

Friar Lawrence married Romeo and Juliet in the hopes that
this will end the feuding between their two households.  Of course, the young couple is
married in secret because neither of their families would have consented to such a
union.  Romeo is forced into a battle with Juliet's cousin on the night of the their
wedding.  He kills Tybalt, the cousin, in a moment of rage.  Juliet's grief over
Tybalt's death at Romeo's hand prompts her father to agree to a marriage between Juliet
and another man.  Of course, her father does not know she is already married.  Romeo is
banished for his actions, which means he will be unable to see Juliet again.  The Friar
proposes a desperate plan because Juliet wants to kill herself rather than marry the man
her father has chosen.  Unfortunately, things continue to go wrong.  Juliet pretends to
be dead but Romeo is unaware that she is pretending.  He returns and commits suicide
before the Friar can stop him.  Juliet awakes to her dead lover and the Friar is unable
to convince her to leave.  Both Romeo and Juliet die after a series of unfortunately
coincidences forces them to make desperate plans which go horribly
awry.