I recently watched 'Alatriste' (good film!), and in the last big battle scene, we have two forces of pikemen opposing each other. Instead of closing and hitting home, they kind of stand a few paces apart, pretty much the length of their pikes, and shake them in each other's faces, maybe occasionally thrusting a little bit. A lot of the actual killing though seems to be done not by the pikes, but my a small number of soldiers who duck under the pikes, scuttle to the other side, and stab at the legs of the opposing force with knifes and swords.
I had never considered this possibility before, but after watching the film, well, it kind of makes a lot of sense. So was this common practice for the era, or from the imagination of the screenwriter?
A friend pointed it out the clip that you're referring to and I can't believe how correct it is. I've seen this before, but there are a few things that must be pointed out.
First, I don't know about the veracity of the soldiers moving out with sword to stab. It seems rather unfeasible because the pikes from the behind the first line would still be lowered, making it very difficult to move forward. The majority of deaths would be from the muskets that was acting as a skirmishing thinner of the primary pike formation. Further, it shows the real weakness of the tercio, artillery.
France forever has been one of the best users of artillery. France destroyed the tercio not by cavalry (which was rendered inept by the pike and shot), not by other pikes (which finished the job). Now, I'm not saying that the a mad melee wouldn't happen but as /u/jaaphoop mentioned, forces often broke before any real slaughter happened.