Why are the events of the Gears of War 3 ending inconsistent with what happened earlier in the game?

Question

SPOILER ALERT

The ending to Gears of War 3 left me a bit confused. After beating the game, you find out that:

... Adam Fenix injected himself with the emulsion to accelerate the transition into a lambent human. He then tests his weapon on himself to see if it kills the emulsion (which was determined to be a parasite). In the cut-scene at the end of the game the weapon actually kills Adam Fenix, he said he is too far into the transition to be cured. This is where the confusion lies. When he tested the weapon on himself, shouldn't it have killed him then, rather than at the end game cut-scene? Surely when he tested the weapon on himself it should of cured him and then consequently not kill him in the final cut-scene.

Answer 1

My interpretation of that is that Adam Fenix either exposed himself to a lower dose of the anti-lambent energy in the laboratory (he wasn't looking that good) or he exposed a biopsy of his tissue to the weapon in the lab. Either way, there would be no point to him fully exposing himself to the device if a successful test means he would die before finishing the weapon.

Answer 2

Surely it's just a way of tying up a rather poor storyline in the first place?

For example, at the start of GoW 3, you see the father die… yet he survives? Why didn't anyone bother to check his body?