salival_sty

I have often gotten into a debate with a few other tool-philes over just this thing (and, by that, I mean the question of "specific intentions," not this particular moment in the video). I figure there are many different ways of looking at meaning/symbol. The following are just a few that I and others have been locked on lately:
1) "Accidental symbolism," where the artist/muscician/lyricist just does what feels cool to him, and if the viewer/listener sees meaning there, all the better;
2) "One-to-one symbolism," where the artist/musician/lyricist has a very clearly defined connection between meaning and image/word/sound, so that the "meat-tunnel" or "shrinking skin" has meaning X, and it is the viewer's/listener's role to "figure out" what meaning X is and the (perhaps guilty) privilege of the artist/musician/lyricist to know meaning X and potentially withhold it; and
3) "Ambient symbolism," where the artist/musician/lyricist has a general sense of what he means to communicate (a sort of atmosphere of intent) and selects images/words/sounds that seem to somehow serve that meaning without working as one-to-one nomenclatures. (Again, this list is not necessarily all-inclusive, just a hopefully helpful step toward clarification of my opinion proper.)

Most of the opinions I see on this site tend to fall under one of the first two categories. 987's comment above, for example, would be an example of an "Accidental" interpretation, while Fatman's comment seems to run along the "One-to-one" line of interpretation. (I only make the latter classification on the assumption that statements like "I don't know what it means" are made under the assumption that there is a set meaning, so if I'm off there, please take no offense, Fatman.)

I tend to think that Tool, in both music and visuals, steers more toward the "ambient" form of symbolism. (There's actually an article, in which the band members talk in an interview about trying to create an "atmosphere" during concerts, that would help support this, for those who believe that whatever's said in an interview must be truth. I'll post a link if anyone shows interest.)
I usually think of Tool's music as being akin to ragas, where the distinguishing characteristic of the form is more its purpose than its form. (Ragas, though somewhat formalized in terms of development, are more involved in creating moods than following set progressions--more involved with feeling than sending messages.) For example, I can't make much sense of "Jesus, won't you fucking whistle" as a specific "meaning"-ful statement, but the line just "makes sense" or "feels right" to me, as it seems to for many others. (Yeah, maybe Maynard passed a whistling priest on a street and thought about orthodoxy and wrote "Jesus, won't you fucking whistle" as a one-to-one, meaning "Is there nothing in traditional orthodoxy," but the idea that the phrase just "fit" musically seems more likely to me.)
And I think Tool's visuals work much the same way: Visually, there's an idea/meaning X (or a set of ideas/meanings) that is trying to be communicated, and certain visuals just seem to "work," to further move an audience toward that message. while others don't. Every last image doesn't equal a specific value that, together, add up to the intended message; rather, each image helps develop an atmosphere, a general sense of the intended message. The end result, then, becomes something that generally communicates much the same message to those who view it (minus those few who have something akin to no sense of humor and just cannot pick up on a general tone), while at the same time striking each individual very differently.
So I think that the specific example in question fits into a general cyclical (i.e., "I've come 'round full circle," vis-a-vis the cycles of life and death) and destruction-obsessed (i.e., the sense that the base of the song/video is pain and its willful, yet helpless, infliction) "atmosphere" of the whole. As the doll's skin shrinks and shows the imprint of a skeleton, so too are the doll's features cracked, so too is the doll battered in the "within-the-head" segment, so too does this one withdraw, does this one repeat gestures, etc. The whole leaves us all with a distinct impression (if nothing else, apparently of awe and interest) that can vary greatly from person to person, yet share common threads with that of our neighbor, brother, lover . . . "Specific intentions"? Maybe not, but I think there is an overall intent, which this particular visual serves in some small part, an overall message on cyclical destruction, withdrawal, doom, vulnerability.