"Saving" Eli without using cheats [Half-Life 2: Episode 2]

(SPOILERS!) Its possible to "save" Eli by killing the two advisor NPCs outside the window. Here's how it can be done without using cheats.
First I have to stack a bunch of nearby props so that I can climb over the fence. There is actually an invisible wall on top of the fence, so I have to build the stack roughly twice as high for me to get over it. Once outside, I grab a barrel and put it on top of the generator nearby. The metal wall doesn't have collision, so I can walk through it and jump over to where the advisors are. Once both of them are dead, I jump back into the map, and carefully walk on top of some invisible walls so I can get into the elevator and trigger the cutscene.
I did this on MMod, but it should be possible to do it on the retail version as well.

half-life 2,eli,episode 2,advisors,saving eli,glitch,