This article is in the process of being updated for the 1.6 patch. Some information may be incorrect or missing.
In PvP, you can Execute downed players on the other team in order to get points. You also have the option of waiting for them to bleed out, or continue shooting at them until they expire, but executing them grants your team a point immediately, and prevents the other team from possibly resurrecting their ally.
Executing a downed target requires walking up to their body and holding the 'use' key for about 3 seconds.