Oh yeah! I just remembered A Thought.
It’s super interesting that Jon needs, essentially, a verbal component when he does any Spooky Stuff. He compels by speaking, often Knows things more easily after he or someone else wonders about it out loud, and smiting requires a full-on incantation.
Meanwhile, no other non-Eye avatar seems to have this limitation of sorts. The coffin sings and Nikola has to dance and have music for her ritual, but I don’t think any non-Eye avatar needs to speak to call on their power.
Elias speaks to insert memories into Martin’s and Melanie’s brains. Both Jon and Elias have to speak or read statements aloud, which is probably just a requirement for the audio format anyway. Gertrude…well, we can surmise that she had the same basic powers as Jon, so she needed words too. (Probably hated that.) Gerry can Know stuff, which doesn’t really take a verbal component, but is often easier with one, as said above.
I mean, provided you were quick enough, you could just…stab Jon before he got through the smiting invocation. Now, he probably looks absolutely terrifying and godly and the avatars are terrified, but you could. In theory.