Rearrange the parts of the sentence in correct order:
At one level,
P-the law in understanding
Q-such cases of violence
R-one senses the limits of

Let's logically link the fragments starting from the introductory clause "At one level,":
The clause "At one level," is naturally followed by a subject and verb combination. Part R ("one senses the limits of") fits perfectly.

"The limits of" requires an object. Part P ("the law in understanding") logically specifies what limits are being sensed ("the limits of the law").

"Understanding" needs an object to complete the meaning. Part Q ("such cases of violence") completes this phrase ("understanding such cases of violence").

Thus, the correct sequential order is RPQ.