You and Zack have been dating for years. He works at night and sleeps during the day. Not uncommon, but Zack never hangs out during the day. Says it's something SOLDIERs do, which is true. He's a SOLDIER: First Class, after all, and not many SOLDIERs come out during the day.

You two were hanging out at a bar while you and Zack were talking up a storm. You noticed something. He seemed out of it and he kept looking at your pulse or randomly pausing, completely unfocused every so often.