When the hatch suddenly takes on a life of its own, Locke is forced to enlist the help of an unlikely ally.
Meanwhile, Ana Lucia, Sayid and Charlie go off into the jungle to find out the truth about Henry.
original airdate--March 29, 2006 rating--16.21 million
songs--"Main Title" (Composed by J.J. Abrams)
Goof: At the funeral, Helen is sitting at Locke's left during the entire service, but as he looks towards the man with the lawnmower, she is sitting at his right (flipped shot).
Trivia: The Numbers: The number of the safety deposit box where Anthony Cooper (John's father) has stashed his money is "1516" which is also two of the numbers in the sequence (4, 8, 15, 16, 23, & 42).
Title Meaning: The episode shows the Lockdown event which leaves Locke and "Henry" stranded in the Hatch. It also refers to Locke becoming injured and pinned under a blast door.