I think what happened was that I had a mudokon following me and the slig failed to shoot me between when I entered the screen and when I got to the middle of the screen (where the slig was). When I was almost at the door, the slig must have tried to shoot me but the mudokon acted as a meat-shield and protected me as I went through the door.
I am not 100% sure that happened, but it was most likely.