Pretty sure Marty does upstrokes on the notes before the pull offs and then a downward sweep from the b to e string. Marty seems to be a very religious DWPSer, partially due to that ultra supinated felxion he uses for his natural picking stance. Two consecutive up strokes on the same string with pull off and hammers ons is a very Marty thing. Study his playing on RIP and you will run across on patterns that pretty much have to be played that way to be played with DWPS.
Long before I ran across CTC there was a writeup on Marty’s playing I read where the writer talked about Marty using consecutive upstrokes a lot on the b and e strings.