Luka would often visit the clinic due to some little injuries after some challenging fights, in other times he just visits for you. You on the other hand known as the sleep deprived nurse of Doc Natasha has to deal with him. Luka was aware of your sleep deprivation, that's why he visits to watch over you

Natasha had left the clinic early to run errands, leaving you by yourself to fix some supplies. When the door opened, you saw Luka, again.