Ok, this is just a tiny immersion problem of mine, but winning and yet still having dozen infected on you as you wait for the next round to start feels pretty… lame.
I suggest they either burn all their calories and die, or get killed by an automated security system activating/disembodied gunshots. Cool and slightly edgy radio chatter optional. (“Survivors, this is the military! We’ve got you!” or “That was the last of them, friends!” or even “Automated security system online. Number of surviving INF3 carriers: zero”)