As you might know, Valve LOVED doing small ingame sequences during HL1's development just for screenshot sake because, Valve. And so when I was looking at the sequence in the back of the screenshot, I at first assumed that it was the "assassin" anim from the "cinematics" folder, but it's not. Well, somewhat. The grunt is definitely using the "assassin" anim in this picture (and on the rest of the screenshots showing this sequence), but the sci is most likely using the beta version of the "barnacled" anim, because it does not line up with the sci's "assassin" anim. Now you know.