E3M7: The Sentinel (Back to Hell)

E3M7: The Sentinel is the seventh map of Back to Hell. It was designed by David Seager.

Secrets

 * 1) East of the start is a room with a pit in the centre. There is a secret door in the south of this room (marked with a red texture) leading to a chaingun and two boxes of bullets. (sector 507)
 * 2) The switch that opens up the doors west of the start also raises ceilings near the start revealing alcoves with barons of Hell (not on easy skill. Going through either of the doors to the west briefly lowers these alcoves, each of which counts as secret, revealing a rocket launcher and a backpack. (sector 36)
 * 3) See #2. (sector 37)
 * 4) The room east of the red key room has an alcove to the south with a red floor. The back wall of this alcove is fake, leading to two boxes of shotgun shells, two energy cell packs, and a soul sphere. (sector 505)
 * 5) The eastern part of the maze in the west of the level has a secret lift (marked with a different texture) leading to a room with a stimpack. (sector 419)
 * 6) From #5 it is possible to head east then north through to a maze which ultimately leads to a room with four barons of Hell, a Spiderdemon (multiplayer only), some ammo, a rocket launcher, a plasma rifle, a soul sphere, and two invulnerabilities. There are three secrets here. (sector 478)
 * 7) See #6. (sector 480)
 * 8) See #6. (sector 508)

Current records
The records for the map at the Doomed Speed Demos Archive are:

Player spawns
This level contains four spawn points:
 * 1) facing west. (thing 325)
 * 2) facing north. (thing 326)
 * 3) facing east. (thing 327)
 * 4) facing east. (thing 328)

Things
This level contains the following numbers of things per skill level: