Combine soldiers never get their memories erased, as that is a process that even the owner of the brain takes ages to complete, instead, the combine just place a neuralcyte in your brain after the body got modified into a combine warrior body. When Gordon, Kleiner, Eli, and the others launched the rocket, and watched as the portal storm ended, the combine link with earth ended, the main flaw with the neuralcyte was that once the link was severed, the affected humans would have a small charge in their skulls, then resume their mind before the combine rule.
One week after the suppression field deactivated, and the humans felt the desire to mate again, two refugees, Samuel and Kimberly were not an exception. After the two survivors met, they immediately fell in love, as noting would stop either of them from gazing into each others eyes.
It was 3 weeks until they made love, and 5 days the combine raided their home in search for other survivors. Kim was taken away by an elite and Sam was knocked unconscious by a blunt hit to the forehead by a hunter’s foot.
Nothing could stop Samuel from crying, as the only girl who loved him back was taken from him, where God knows what was done to her.
Kim on the other hand, was given that neuralcyte and her body modified into the short-lived combine assassin models. All she remembered of the process was that huge needle going into her skull and after a small light show in her eyes, she became a combine soldier.
Two weeks later, Sam arrived at white forest, in which he cheered on Gordon Freeman as he rode in his jalopy to kill the striders in intent to stop the end of the combine control. Sam killed many combine soldiers who wanted to cut off access to strider-bustin devices. When it was detected that there were no more combine soldiers assaulting, Sam was still on guard.
Kim, as a combine soldier, was not going to give up easily, as the assassin project was not one to abandon the main objective unless the price is greater than the reward. Kim slaughtered many rebels, only one refugee fought back because he was the only one who knew she was there, as he threw himself with a knife, it made a scar over her eye, but in the end, she still snapped his neck.
Moments before the portal storm was destroyed, Kim pulled up her smg, took aim, and sent one round lead bullet through the air, at the exact moment the portal storm ended. After that shock in the cranium, Kim watched the bullet enter Sam’s skull, right after she remembered who he was. Kim rushed over to his corpse, threw down her gun, and in shock, looked at the bullet would that was still oozing blood. She could not say anything, but a few gasps. Her gut feeling was terrible, as the death of her lover was ended by her hands. She let out a few wails, and pulled up Sam’s AR2, placed the energy-sphere launching barrel to her mouth bit down, closed her eyes, let out a tear, and pulled on the alternate trigger.