Episode 22 of "Lost"
s01e22 Born to Run

Jack suspects foul play when Michael becomes violently ill while building the raft. Suspects include Sawyer and Kate who compete for the last seat on the raft and do anything as possible to make sure neither one gets it. Meanwhile, a secret from Kate's past is revealed to the other survivors on the island---that she is a runaway fugitive. Also, the mysterious hatch is shown to Jack and sides with Locke over an opposed Sayid that they should open it. Walt gives Locke a warning in not opening the hatch. Walt also admits to his father Michael that he burned the raft the first time and changes his mind over not leaving the island once he realizes Lockes' plan over that hatch. Lastly, flashbacks of Kate's past reveal happier times with the "love of her life", Tom (guest-star Mackenzie Astin) prior to his death and a visit to her ill mother.