Not enough detail in the comic to tell whether it's a striker or hammer-fired pistol.
Most striker (and some hammer) automatics cannot be decocked without pulling the trigger on an empty chamber.
And got those that can, you either have to pull the trigger while holding the hammer back and lowering it manually, or by flipping a separate switch or button.
If it could be done by moving the slide back and pulling the trigger, then holding the trigger down while firing the gun would result in full-auto.
Word is the fucking worst.
"Hey Word - I need to adjust the header for just this page."
"No."
"Can I just remove the header in this page then?"
"No"
"How about the watermark? It's in the way on this page?"
"It's tied to the header."
"... I'm gonna have to make like 12 documents and combine them in Acrobat aren't I."
"Please log back into OneDrive."