The glitch shown in the video below is usefull to teleport an alien without actually teleporting it. While the teleported alien count is incremented, the alien is still here, near of the teleporter. You then skip bringing another alien from far away. This glitch requiring good timing and perfect positionning, it is more likely to be used in a TAS.

Note: Even if this glitch was done successfully 4 times in a row, saved time on the mission would be like ~1 minutes...

Credits: TLD