The other of the locks on the safe opens with Winfriede's voice.
How to get it?
It is fixed
You mean, how to record it?
There must be recorder laying somewhere here.
Did you look at in the box at the bedroom?
You now have a recorder. But it is broken. Fix it.
Now just use it on the door to record some of Winfried's voice into it.
Now you can use the recorder with the voice on the safe to open the other lock.