Well EQ wouldn’t crush the heart because that would kill them both.
I didn’t say the EQ would be the one to crush it. But somebody might, and that would kill them both.
And we know that the heartless can live without their hearts provided that they are kept intact. So a heart split wouldn’t need to happen for this to play out.
Not sure what you mean by this. If Regina’s heart was fatally injured while in the EQ, it would kill her – both of them, I mean. And if that happened, someone splitting their heart for Regina would be one known way to revive her.