Star Trek Picard: Every Easter Egg & Hidden Reference From 'Broken Pieces'
16. Reactivated EMH
The EMH is back after Agnes disabled him and allowed Bruce Maddox to die a weird, veiny-faced death in "Stardust City Rag".
He tells Picard that Jurati injected herself with a hydrogen compound (noranium hydride) to neutralize the viridium that was already in her system. Viridium is apparently what the glowing Jolly Rancher was made out of that Commodore Oh gave Agnes in last week's flashback.
In Star Trek VI: The Undiscovered Country, Spock slapped a viridium patch on Kirk's back so the crew of the Enterprise-A could track Kirk from two sectors away.