Keys as a physical thing.

My player playing the Detective Pregen lightly deathed Smersh and no sooner had he done so the Aggregate Hospital Sweep came along to pick him up.

Our detective didn’t want that!

“I attack the hospital sweep!”
“That’ll be 50 flow please. Breaking challenge.”
“Whaaat? No way. I will move him some other place and destroy the tracking device they use to keep track of him!”
“Oh… Still a breaking challenge… flow cost… Material… Lets say it’s a chip in his chest.”

After the game I’m thinking it’s still 50, after all as it’s Aggie’s tech interfaced to Smersh. Although it’d still be included in Smersh’s backup for if he were more heavily deathed.

Plus Switching sets a precedent for key interaction.

(We followed up with a Shaping challenge to “woo” the deathed character to believe that his death was actually art and he’d just forgotten the memory of it being his idea.)

The best way to destroy someone’s Key is to get them put up for a deportation vote. Just launch a viral media campaign to frownie the shit out him and let the Aggregate crab him.

I think you made a good call.

The Key is very difficult to destroy, since it’s grown into you at a cellular level. But it’s not impossible! I think a Breaking Challenge against the Aggregate is a good call, since even though it’s in you, it’s what makes you a part of the station.