Hey! Since Rica took the lead on this event I don't want to call this answer said and done until she gets back since that will still be before the event starts. But I didn't want you to think we'd missed it either.
My take is that he can absolutely try, but there are no actual spirits within the dome to reach because no one has actually died there. All "deaths" were virtual. And the dome itself blocks all outside connections.
That said, we might allow for some kind of reaction (virtual spirits maybe?) since the wardens want to provide a good theme for everyone! So, we'll get back to you on whether there are any options to explore with this.