Rainbow Six Extraction: How to complete MIA Rescue missions

If you are taken down in Rainbow Six Extraction and are not revived or removed by a teammate, the Operator you were playing as becomes unavailable for deployment until you return to the map where you were taken down and complete an MIA Rescue operation. Any region with an MIA Operator will have a red Operator icon and a number showing how many MIA Operators there are under the Play tab. The same red Operator indicator on the region screen indicates which maps have MIA Operators on them. To see which Operators are missing from those maps, highlight them.

When you start an incursion on a map with at least one MIA Operator, the first Sub-goal zones is always an MIA rescue mission. The first step is to track out the MIA Operator. Various recon gadgets, such as the Recon Drone and Pulse's Cardiac Sensor, can assist with this. If you don't have any recon tools, roam around the map until you discover them (they won't be close to the starting place). If you're playing alone, this can take a long time, but if you're in a group, you can split up and cover the map more quickly.  

Don't expect your Operator to be in the same spot they were when they were taken down. The Parasite will have absorbed the Operator into an Archan Tree by the time the rescue crew arrives. The MIA Operator is equipped with a tracking device, which will beep as you approach.

Once you've located the Archan Tree, press and hold the interact button in front of it. Let go of the MIA Operator and shoot the Archan Cells coming towards the Tree when you see red indicators arriving from the left on the HUD. When the Anchor Points open, you can blast them to temporarily destroy them, making your mission easier. Switchback and forth between tugging the MIA Operator and shooting the Cells and Anchor Points until the Tree lets go of the MIA Operator and you lift him over your shoulder.

Following the signpost to the extraction spot, place the MIA Operator in the extraction pod. If you're extracting as well, simply place the MIA Operator on the extraction pad's floor. Your MIA Operator will be available for deployment in your next incursion whether you safely extract or not, but their health will be lowered for a time, thus it's best to let them rest for a few more incursions.