My group thought that too about a month back. Since then we have completed it.
There is a path that lets you skip everything before the first boss. (which means timer wont start until the first boss)
You can skip all the ads in the first section of the crypt by running to the boss room and going into sneak behind his throne
You can skip the 3 minotars before the last boss if you go to the right and time everyones run for the door.
Bloodyhorn is bad about skipping mechanics and coming back to them later, so a crontrolled burn works better than a full out DPS burn.