This is the button that Heinz Kruger pushes while exiting the Rebirth Lab after killing Dr. Erskine, immediately after Steve Rogers' transformation is completed. It can also be seen when Rogers and Agent Carter first enter the lab.
This button was also carried by Joe Johnston, the directer, while filming and he would use it to jokingly "blow people up."
More from Captain America: The First Avenger (2011)
