One thing I do notice is the structure of the entire production of this song. After the massive success of "love the way you lie", someone figured if they released another song with the same structure (but with a different melodic arrangement), it may gain the same, or close to the same amount of success as the first song did. Listen to "I need a doctor" and notice how many similarities exist in the production beat pattern, style, structure, and arrangement. Also notice the style of rapping, arrangement of verses, and the chorus. Same set up structure, but with a different chorus singer and third verse rapper. It's too bad that despite the fact that the overall production structure of "I need a doctor" was similar to "love the way you lie", it didn't do as well or even cross over into urban (even with Dr Dre in it), the same way "love the way you lie" did.
This is not the first time someone has used similar production structures in a second single to what was created in their fist highly successful single...