Juggling books also make the joke that being able to juggle one ball is not the test for a good juggler, but for decent telekinesis (one ball means no hands, right? [sadly this is the best joke you'll find in most juggling books, which is why jugglers are jugglers and not humor columnists]). This test also fails to apply to amorphs, because if you throw a ball to an amorph and insist that he/she/it not sprout any hands to deal with it, the amorph will simply eat the ball. This actually has a much higher entertainment value than juggling, and ensures that nobody will be doing any juggling with that ball anytime soon.
The point of all this is that if you'll closely scrutinize the Schlock Mercenary archives, you'll find that Schlock has never before had more than two hands. This is because until now he's never needed more than two hands. In this strip, however, he needed one hand on the plasma cannon, one hand on Massey, and one hand to help him look like a superhero while flying.