Lyric discussion by Eddiemarz 

Cover art for Careful with That Axe, Eugene lyrics by Pink Floyd

I’m much more familiar with the Ummaguma version, but along the lines of the axe murderer theme I imagine the repeated whispering of “careful with that axe, Eugene” being the voices in the crazy guys mind and the since they keep repeating and getting louder he screams and then makes his kill which is the second scream.