I hear ya there bud. However, I believe it to be more like a homing "sabot"."It's like a mini ICBM. Multiply it times 30, THAT is why the Serp is awesome.
The Serp itself isn't a missile; it carries a missile that it launches, then dies, because it has nothing left inside it to power it or give it direction. It's a dedicated -single missile launching- unit, despite the fact that it does look like a missile itself." -CannonFodder100
Let me theorize how it may work.
When the Serp comes within range of it's target, it sheds it's outer casing. Then the rocket motor ignites and it then homes into the target, like a radar or heat seeking missile.
Perhaps this video on Youtube can explain a little of what I mean:
Imagine the Sabot round inside the "casing" is actually the Serp missile.
I mean darn it! I love 'em sooo much, yet I'll blow up if I try to hug 'em.