It fit the vibe just fine to me. The Infamous has a very jazzy vibe and it was perfectly in line with the other Q-Tip joints in particular, as well as Trife Life.
Q-Tip explained it on Complex and the Red Bull Music Academy how the big key to The Infamous' sound is that it was dark, not hard, which js why there was room for beats like Give Uo The Goods, Temperature's Rising, and Drink Away the Pain. Its not a hard song necessarily but DATP has that same kinda late night, quiet storm vibe as a lot of other songs on that album; those saxes on QU-Hectic and Cradle to the Grave are similar too