Terneves Ruins Cutscene?

I had just recently gone to Terneves in order to buy a new horse to breed in the new update, and I went into some ruins (https://imgur.com/a/8s1km5A).

What I was greeted by was a cutscene with a person named "???" speaking about how villagers caused a cave-in and he was chipping away at the wall. He then walked up to a pile of TNT and blew himself up, opening the passageway to a cave.

I didn't go in the cave since I had a full inventory of loot and assumed it was just another location, but when I got back the cave was blocked once more and the "???" man was gone.

Does anyone have any idea what was in the cave or what the purpose of the cutscene was?

 

He thought they were digging a wall, but as soon as he found out about their death, he went crazy and blew himself up.

 

I know this, but there was a cave back there that is no longer reveled for me. I was wondering what would have been inside if I had gone in instead of going back to Detlas to drop off some loot.

 

Here's a video from myself

 

Huh. Alright. Thank you for the video!