Let's assume that the ER=EPR conjecture is true, that is, if me and a friend take some set of entangled particles, divide them in half, separate them in space, and compress both halfs into black holes, that those black holes will connected by a wormhole.
It seems like this phenomenon can be used to communicate across the event horizon of a black hole. If me and my friend coordinate the time correctly, he could jump into a black hole, and then collapse his entangled particles. We could use the wormhole we just created to communicate superluminally.
Is there anything wrong with this?