I have a prediction.
The new Boss launches with the factory expansion. In the short clip we see him hitting a wall with hammer.
I think that the boss will be locked away for a set duration on a factory raid. Meaning he will eventually break through the wall, giving you time to fight pmcs.
Alternatively you can blow the wall up and release him early..maybe? (A la street trailer destruction)
Once he's broken through, you'll need to kill him / pass him to enter the hole he made, to gain access to a usually inaccessible part of the map, where he was hiding. Area could contain good loot etc.
Encourages players to hang around for bosses – rather than rush them like Killa
Im probably wrong. But think it'd make a lot sense.
Edit: alright he's hitting a body. Missed that. I'll stick with my prediction.
Source: https://www.reddit.com/r/EscapefromTarkov/comments/o1afpj/factory_boss_mechanics/