The verb agandallar means to get something by being a gandalla. Gandallas live by the maxim el que agandalla, no batalla which means "that who snatches does not have to struggle".
Note: In Mexico City, as in any other place where car-rides take an obscene amount of time, people hate riding in the back seat, especially "riding bitch" (i.e. in the middle, with no window). A civilized way to deal with the problem of assigning seats when there are two or more passengers is giving the right to ride "shotgun" (i.e. in the passenger seat) to the person who first shouts shot (short for "shotgun"), and the right to ride next to window in the back seat to the person who first shouts shot güindou (from window). However, cynical gandallas have circumvented this unwritten rule by popularizing the axiom gandalla mata shot, which means "grabbing the seat overrules shot". Beware.