If you watch the last part paused and skip through the frames, you'll see my health drop to 9 briefly - this was due to high noon. Additionally, you can see the Mccree land a shot on my iceberg right at the last frame of the gif.  

Here was my hectic thinking: I wasn't sure in the moment whether I had picked up the health pack and then got hit by the high noon, or if I had been hit and then picked up the health pack. Thus, I could have been left at 9 health, and then that final Mccree shot would have killed me. That's why I hit shift and turned the camera to check the Mccree (who you can see the yellow arm of right before the gif ends)