Originally Posted by Jay3
It's more of a figure of speech, the "first one in, last one out." It's not even actually always true. It's a shorthand way of conveying someone goes the extra mile, does anything they can to get better.
Well I've known plenty that did the first one there, last one out, thing. An hour or two early for work, always staying hours after their day ended, and occasionally showing up on days off kinda people. I guess since I've seen it, I didn't realize people also use it in a figurative way.