You know, Hei, you may be right indeed! there theoretically may be time correspondence in the context... E.g. they had learned that their daughter worked as a strip dancer. So when they rushed into the cabaret where she worked, they were already horrified )) ^__^ they knew what to expect ))) Still, the previous speakers may be right as well )

It means that the scene[ maybe a murder] was terrible so when they looked at it they were very frightened by what they saw.

If you look at the meaning of the words, you will realize that it does make sense. 'Take a look' means.......to look at with attention. They took a look (that became a horrified look)........ The result of the 'look' was horror. They took a horrified look............ The past participle is used as an adjective. You could also say it like this: They looked, horrified at the scene in front of them.........past participle phrase modifying They.

Don't worry too much about the logic of time here. The idea is that they were horrified as a result of looking. "Took a look" by itself is very neutral. "They took a look, and were horrified" makes sense but that's two events you are describing. "They took a horrified look" condenses it into one phrase. Very effective for emotional impact. "To take a look" can indicate either a short time or a long time. So it is also possible that the looking and the horror happened at the same time.

By saying 'They rushed in and took a horrified look at the scene in front of them', the author is describing the emotion of the people when they looked at something shocking. I don't think it is impossible to 'look and feel' at the same time. We are always feeling something when are looking at something. I am feeling a little excited while I am looking at the screen, writing this statement. You are feeling curious while looking at the screen, reading what I've written. If I enter a room and see someone lying on the floor, I would be instantly shocked and have a horrified look on my face, at the same time. Hope this helps :-)