Eddie being killed at the end of S4 is already infuriating, but it’s even worse when you remember there was another gate nearby that should have opened when Fred was Vecna’d. Assuming the gates have to attach themselves to something physically (they’re never shown floating in the air--Patrick’s gate was at the bottom of the lake, not above it where he actually died) there should have been a gate on the ground, on the road where Fred died. That gate easily could have been used as a backup escape route for Eddie or Dustin to use if/when being overwhelmed by the bats. Also the fact that no one thought to make covers for the gates to prevent the bats from getting through was... a choice