OK, here's how cred/stage points get distributed, just to clear confusion.
When a player dies, all enemy units who did damage to him (ANY) damage, get evo/cred in proportion to the amount of damage.
Example: You and me both dretch a mass driver in the chest, leaving him with 4 hp, and a 3rd hits him in the foot, for the kill. MD gives 2 evos: I get one (48% damage dealt), you get one, then the 3rd gets nothing because there is no more left to distribute.
Example 2: Naked human comes running around a corner, and you get the headbite, but a friendly goon eats the human before you can make the kill. Goon gets the evo because he did 100 (or 160), where you did only 96.
Stage points:
When an enemy dies, you get the point toward next stage IF your team did over 50% damage to him.
Example: Human runs out to attack, but lucinoobs blast him down to 51hp, and the knockback sends him into a party of goons. Aliens get stage point, because they did 51% damage, where the luci only did 49%.
Example 2: same situation, but the luci blast hits him and leaves him at 1hp. Aliens get NO points toward next stage for this kill, because they did less than half.
Example 3: Dretch gets shot by a rifle down to 10 hp before dying to a turret. Humans get the point to next stage. (60% damage vs 40%)
Example 4: Dretch gets shot by a turret down to 5 hp, and rifle spam finishes him. Humans do NOT get stage point, because they did 20% damage and turret (aka world) did 80%