XCOM: Enemy Unknown

[TinCow]

Of course this would be different stats on Classic since Sectoids have one less health, but the concept is the same. So heed my warning, ye fellow fighters of ETs. Health and mindmerge matters beyond what I had even bothered to consider.

Yet another reason to try and go for the source of the merge rather than the target of it, since you can kill the weaker one and take out the stronger one at the same time. On classic that's actually really easy since you can dispose of the entire pair with a single grenade; when the source of the merge has 4hps that's not an option, but the theory remains the same. Grenade the source, dropping him to 1 health and insta-death on hit. You'll also frequently destroy his cover in the process, significantly increasing someone else's odds of the finishing shot.