Leiden is located at a 20-minute train ride from Amsterdam airport. The Leiden University Medical Center (LUMC) is situated near the center of Leiden, at a few minutes' walk from the Leiden central train station.
The section EM is located in the research building of the LUMC (building 2). A schematic drawing of the direct vicinity of the research building can be found here and a zoom-out region is shown in this document.