You choose the one currently in play to go to the graveyard, with the second Sharuums trigger being put on the stack after the first has gone to the graveyard
Escalate 702.119a Escalate is a static ability of modal spells (see rule 700.2) that functions while the spell with escalate is on the stack
Gaining a mass number of counters, and burning opponents is the first thing that happens when the Vivi player storms off
The Strong Ultimate is Immediate and Doesn't Kill Sorin - There are a few modern planeswalkers, such as Gideon, Ally of Zendikar, that could be dropped quickly, and used with it's ultimate as soon as it arrived, but you had to kill it
I feel like the significant mana costs and overall less value-happy orientation of activated abilities have kept this artifact from becoming a popular darling, but the power is undeniable
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