He walks over to the lab and touches the equipment as the police approach.
Walt’s inside the Alquist’s meth lab, slowly walking between the lab tools. The place in which Heisenberg was created is the same one in which he dies.
Before dropping to the floor, he leaves a blood mark on one of the tanks. This perfectly links to the Fe Li Na hypothesis of the episode title.
The lab collected tears, meth, and blood from Walt
In the background, “Baby Blue” starts playing, a reference to the name of his cook, the Blue Sky Meth
In doing this Walt also removes any suspicion from Jesse. He touches all the equipment leaving his fingerprints and Jesse was wearing gloves so there’s no trace of him ever being there.
To help improve the meaning of these lyrics, visit "Felina" by Breaking Bad (Ft. Vince Gilligan) and leave a comment on the lyrics box