This is a really bad idea. There's a killer on the loose here. Go get help. What? Go!...

[at the hospital, Tree sneaks behind the security guard. She deftly takes his gun from the holster and points it at the guard] Police Officer: [trembling with fear] This is a really bad idea. Tree Gelbman: There's a killer on the loose here. Go get help. Police Officer: What? Tree Gelbman: Go! [the guard runs away. As soon as he is out of sight, he starts yelling] Police Officer: She's got a gun! She's got a gun! [Tree cocks the security guard's gun and storms into the OR. Inside, Lori reads Tombs' medical record, failing to notice that Tombs takes a knife and is about to stab her] Tree Gelbman: Lori, move! [Lori moves to the side. Tree shoots Tombs three times. The murderer is thrown against the wall and collapses on the floor, dead. Tree grabs Lori's hand] Lori Spengler: [gasps] What...? Tree Gelbman: Come on, we've got to move. [Tree pulls Lori to the door] Lori Spengler: What's happening? Tree Gelbman: I'll explain later. Move! [meanwhile, at the lab, Ryan has Sissy nearly ready to operate. The lights at the campus go off and back again. Unfortunately, Dean Bronson figures he was distracted, and hurries back to the lab with two security guards. Samar and Dre push a couch against the lab doors]