Laurie Anderson, musician, performance artist, and widow of rocker Lou Reed, went into a hyperbaric chamber in Chelsea's Pure Flow spa last week ... and couldn't get out. The 67-year-old texted a friend when the chamber's zipper got stuck and she started experiencing shortness of breath, and that friend called 911. The FDNY arrived on scene to find Anderson had already managed to escape from the $100-per-hour chamber, which spa-goers visit for oxygen treatments. "She is shaken up, but she's OK," a neighbor tells the New York Daily News. The spa denies any malfunction.