How to beat the Spillover Crisis Event in Rainbow Six Extraction

gamepur.com:

As part of the first post-launch DLC for Rainbow Six Extraction, Spillover marks the first in a series of Crisis Events. Whereas the other new additions, the Operator Zofia and the Auto Turret React gear, will stay in place, Spillover is a limited-time event running until the 11th March. It’s a swarm or horde-like defensive mode, pitting you against an increasingly tough army of Archaean forces, so you’ll need to play it tough AND smart if you’re to get out alive.

It varies from your standard missions, in that it all takes place within a single subzone, each with nine ‘colonies’ you’ll need to take out within a 25-minute window. You do this by placing a Dissolution Agent canister in each one. These are available from the extraction pod, and if one gets destroyed by those pesky Archaeans you’ll need to head back for a new one, so it’s usually worth your squad taking more than one on your travels.

Once placed in the colony, it will trigger an enemy assault which you’ll need to fend off for 90 seconds in order to enable the corrosive chemical to work its magic, before you move on to the next one. Successfully destroying all nine colonies will bag the maximum rewards but, as always, be prepared to evacuate early if things aren’t going your way. You can claim the first XP reward after clearing two colonies, and a second after the next three, leaving the remaining four as quite the challenge in order to top off the haul ― along with a few skins and accessories on offer for completing the additional Studies challenges.

You can tackle the colonies in any order, with each having a certain type of enemy mutation attracted to them (3x Elite, 3x Blinding Spores, and 3x Cloaked).