Ring anchor / ring beam reinforcement partially severed

These are 12 iron rods. My concern is that if I expose the iron rods further, it will worsen the situation and cracks will form. Can you tell me what the tool is called?

What you have not shown a picture of is the drill core; I do not see any reinforcements here. And in my assessment, you have not drilled through any ring beam, but through the brick wall below.

Well, he must have gotten it from somewhere that he cut through reinforcement. Have a structural engineer take a look at it. It was already dumb enough to just start drilling there... are you even allowed to do that without the consent of the other parties? Even dumber now would be to botch it without inspection and then in winter, with substantial snow load, the roof suddenly gives way or something like that...

If it were your own single-family house, okay. You can do whatever you want there, but as far as I see it, you live there with 8 or 10 parties? They have a say when you drill through structurally relevant parts and then do a shabby repair...

So I just got feedback from an acquaintance who works in construction. It is probably a ring beam that absorbs the forces from the stairwell, since there is only a window front there. He says it’s not that bad because the ring beam still rests far enough inside my apartment. He also said there is more than enough iron in the ring beam anyway. What do you think about that?

Ask a structural engineer. The roof rafters rest on them.