Wow this was a roller coaster of a thread.  Here is how I read the scene:

Once Murphy is shot and it sinks in.  A switch is thrown in Harry.  You can tell by the way he is talking.  They're trying to get him to stop and he's dismissing him with the same tone that someone would use to say "Just let me wash my hands, then we can eat."  That is the emotionless logic of a sociopath who treats murdering Rudolph has a banal task he needs to complete.  The holy lightsaber, which Harry could pass his flesh through previously while feeling just a warm buzzing sensation now sears his flesh as if he is pure evil, which he is that that moment.  The sword then has the same affect on harry as it does on the monsters.  Once Harry snaps out of it, Butters could have pushed the lightsaber through him and it wouldn't have harmed in again.  Harry is going to have another scar on his arm that reminds him not to become a monster.  The sulfur smell was the signal that Harry was seriously in the wrong, I don't think it has anything to do with an outsider influencing Rudolph.  It has everything to do with Harry being evil in that moment and the sword telling him a resounding "No."

Perhaps your geolocation makes a difference as no one else can see it, including me. Are you using the kindle tablet?

It's a Google tablet, but definitely a tablet.  Pretty weird! 

See if this works:

https://ibb.co/GxBJWGg

https://ibb.co/RSMVhPr

as someone else mentioned, I did not pre-order the book period so maybe let me download the sample?

If anyone is interested, you can read chapter 4 and part of chapter 5 by viewing the sample on Kindle.

Harry has another soulgaze, hehe.

I think the Time Travel is key because why else call the hounds that specific name?  If Jim just wanted to throw a demon doggy at Harry and Eb it could have been anything.

One thing that I noticed during the Hounds fight is that twice Eb says that "concentrated fire works best" and Harry doesn't even try to use fire?  I think the only fire he casts is flickum bickus.

The room itself surviving doesn't mean that everything in it did. (I mean, a basement room wouldn't generally be completely destroyed by a fire/collapse of the building above it, would it? Or am I way off base here?)

The trapdoor survived with just scorches on it, but Harry thinks the floor caved in over the room and the stuff was burned/melted.  He can see marks on the floor where his lab stuff *was* and he can also see the summoning circle in the floor.  I think that people have been acting like the room was untouched by the fire, but it wasn't.  Aren't there somewhat contradictory WOJ's on Little Chicago?  One time he said it was melted into a slab and another time he was more cagey and did one of his typical "Nothing could have survived all that heat" lines. 

Something struck me in the scene where Harry summons Molly in order to get her to craft the doppelganger ring for him.

"Hah!" she said, grinning.  Then her expression sobered. "I've done some work like it lately..."

Did she make some sort of shapeshifting or doppelganger magic item in a short story or something that I missed?  Or is there someone else running around Peace Talks while not currently in their body and/or shapeshifted/altered?

One other thing, did Evil Bob still have all of the knowledge and experience that regular Bob had?  I think he did have those "memories" so he would have seen Harry making...how many staves over the years?  Harry makes them as McCoy taught him.  It seems likely that he would thoroughly know McCoy's style.