Parem

Parem was a Romulan officer accidentally phased by a Interphase generator being tested aboard his ship. When Geordi La Forge and Ro Laren were also acidentally phased by the same device, he attempted to kill them rather than let the secret of Interphase technology fall into Federation hands. He was pushed through an outer wall of the Enterprise-D in 2368 whilst trying to kill Ro Laren. Presumably he died in the vacuum of space. (TNG: "The Next Phase").