Blackwolf got a point on making CODE to acutally allow beams or solids in this matter to be broken down and blown out.
if you look at games like Half Life and Quake, there are for examples Brushes (the simplest shape units like boxes, triangles, cylinderes etc.) that make up the world you run around in, that are flagged using a mission editor such as Worldcraft were it makes the solids, breakable relevent to where the attack is coming from, and the material.
Since in HL, the only time the "bodies" for example carve in a similar way is when they are blown up. Every HL model has a subobject for these effects, such as the Damage MODEL that shows-up or in this case, spawns, once the ship is destroyed.
to add more subobjects to be blown off would render the game lagg extensivly due to the polygon limitations of each model. In HL its possible because its the entire world these polygons are made of, but its only the ones viewable by the gamer that break down visually, if any others break while ur not in view of it, it isnt drawn out, but the math/code made it happen (but not visually).
its possible but would render the game unplayable if u say had a Lucifer and a Orion shooting each other, the chunks would be huge...
unless they were just plates getting blown off...