Player death at the end of Phobos Anomaly (level E1M7):

After the player kills the two Barons of Hell at the end of
Phobos Anomaly, the walls of the star-shaped room drop,
allowing access to an outside teleporter.
The teleporter transports the player to a small, dark room
with a green-acid floor, and the player is surrounded by
monsters.  Here, the player character appears to be killed
before the end of the Episode.

For better or worse, this is the NORMAL ending for this
Episode of SNES Doom.