I'm sure a lot of you have read guides before trying this.
You can indeed hit escape and load the current save before the cutscene ends. If you get attacked by the alien a second time before hitting a new save point you need to load the previous save point!
I was attacked in the very last part by a facehugger from behind, it killed me. But I loaded the previous save point and the achievement popped for me when I finished!
I guess this will also work if you get hit by the trams.