NURSE SAM CONFRONTED BY NEW LIFE AND SUDDEN DEATH; DR. CARTER ENTERTAINS GIRLFRIEND AS THANDIE NEWTON GUEST-STARS -- Life and death assume an even higher profile as single-mother Sam (Linda Cardellini) treats an abused and newly pregnant teen (guest star Rheagan Wallace) as well as a wife (guest star Marin Hinkle) who sees her injured family melt away after a car accident -- while Dr. Carter (Noah Wyle) takes a holiday to show Kem (guest star Thandie Newton, "Mission: Impossible 2") the wonders of a wintry Chicago. Elsewhere, a risk-assessment expert (guest star Richard Kline) is hired to observe the E.R. and is shocked at the abounding mayhem -- especially when Sam roughs up a patient's friend. Abby (Maura Tierney) and Dr. Pratt (Mekhi Phifer) restrain an undocumented man (guest star F.J. Rio) who wants to check out despite testing positive for tuberculosis while Sam is quizzed by her son Alex (guest star Oliver Davis) about her interest in Dr. Kovac (Goran Visnjic). Laura Innes, Sherry Stringfield, Sharif Atkins and Parminder Nagra also star..