The Hour Of Joy Would Have Failed if the Innocent Workers had been spared
First off, in Chapter 4 we learn Prototype forbade anyone from leaving the place to ensure the research is hidden. This is supported in a Chapter 3 death message:
THIS RESEARCH MUST STAY BURIED. NOBODY MAY LEAVE.
This is supported by Poppy's remark in Untitled Tape.
Poppy: [Deep breath] "Prototype says we can't leave. Not now. Not ever… I hate him. I hate him, and I hate this place, and I hate that he's… Right. He explained everything, and he's right. We can't leave. It's too risky. What they did to us… We can't let it happen to us or anyone ever again."
It'd be pretty much impossible for the toys to hide their existence from the innocent workers after killing the ones that did not know. PW says in the Orientation Notebook that the older counselors in Playcare knew and the younger ones didn't.
And The Higher Up offices are way above where the labs and the prison were.
Their unawareness would mean they wouldn't see the toys as righteously angry, they would see them as monsters who randomly showed up and started slaughtering coworkers. The would be seen as "the bad guys". If they got the chance to live, they would panic and call the cops (who Playtime had bought off) or the government (who would be the LAST people who should hear about these experiments)
The Hour of Joy would fail if any of them were spared. And if there were workers who were genuinely willing to never leave the building and keep mum? Well, if YOU were The Prototype would you risk it?
It's exactly the fact that Prototype HAD to kill everyone in the building for his plan to work. It was either nobody or everybody.
But the other fact is prototype DID TRY to minimize HOJ casualties. The Orientation Notebook shows HOJ was "conveniantly" scheduled to happen when not on a tour day.
Mondays, Tuesdays, and Weekends.
If you check your calendar, you will see that August 8th, 1995, fell on a Tuesday. This is a little too specific to be a coincidence on Prototype's part - and to me it suggests that he tried to avoid a little bit of bloodshed when he had the ability.
Prototype didn't have everyone killed because he was a bloodthirsty monster, he had everyone killed because he HAD TO. Everything he did had a reason, not necessarily a reason everyone would agree with, but he didn't do it just to be mean.
