How do I kill two people with one bullet?

Question

In mission 10, "Gallant Thief", there's a challenge to kill two people with a single bullet. How can I do that? Do all bullets penetrate? Is there any specific place that it's really easy? I didn't really see a good opportunity for it even.

Answer 1

Penetration is depending on the weapon's power as I noticed.

There is a good spot, but you got to be very quick on the trigger (spoiler):

After you bring the president out of the cell, the whole prison gets hit by an airstrike, and then there are soldiers helping each other to walk (=easy target for double kill), but they most of the time explode rather quickly in the fiery mess...