In this task, you will be shown an extract from a movie plot. You need to read the extract and create questions that can be answered from the extract. The questions should be well-formed and grammatically correct. The questions should be completely answerable from the given passage and should not require any external knowledge. Subjective questions are not allowed. Create questions that result in factoid answers. A simple rule of thumb to decide whether a question is factoid or not is to see if two different people with average reading/comprehension skills would come up with the same answer after reading the passage.

Let me give you an example: Twenty-year-old Will Hunting of South Boston is a self-taught, genius-level intellect, though he works as a janitor at the Massachusetts Institute of Technology and spends his free time drinking with his friends, Chuckie (Ben Affleck), Billy (Cole Hauser) and Morgan (Casey Affleck). When Professor Gerald Lambeau (Stellan Skarsgard) posts a difficult mathematics problem as a challenge for his graduate students, Will solves the problem anonymously, stunning both the graduate students and Lambeau himself. As a challenge to the unknown genius, Lambeau posts an even more difficult problem. Lambeau chances upon Will solving the problem but Will flees the scene. That night at a bar, Will meets Skylar (Minnie Driver), a British student about to graduate from Harvard, who plans on attending medical school at Stanford and gives Will her phone number before leaving.
The answer to this example can be: How old is Will Hunting in the movie ?
Here is why: This is a good question which has a factoid answer.

OK. solve this:
Berlin in 1945 after Germany's defeat in the war. The former military surgeon Dr. Hans Mertens (Ernst Wilhelm Borchert) returns home from the battlefield to find his home destroyed. He suffers from the terrible memories of the war and becomes an alcoholic. A photographer and Nazi concentration camp survivor, Susanne Wallner (Hildegard Knef), finds him living in her apartment as she returns home and they become roommates and even friends. Eventually, Mertens meets his former captain Ferdinand Bruckner (Arno Paulsen), who had been responsible for the shooting of a hundred civilians on Christmas Eve of 1942 in a Polish village on the Eastern Front. He is now a successful businessman, producing pots out of old Stahlhelme, the German military steel helmet. On Christmas Eve, Mertens plans to kill him, but Wallner stops him at the last minute. They decide to have Bruckner put on trial then, and the two start a new life together.
Answer:
Who stops Merton from killing Ferdinand bruckner?