Mission five of MSD, any hint how to handle it?

The last update added to the game "Mission", which are staged with preseted deck and no base upgrade. The first 4 ones are quite easy, but I m struggling at the 5th one.

This mission give you Tarma, Fat Tarma, Drill Slug and Sand Bag, with the goal to stay alive 80seconds.

Problem is, the map start with 5 wall of worms, which are suicidary charging powerful unit if activated by one of your unit going near them. Basically, if activated, it s game over since your unit can t spawn and kill them fast enought.

Add to that a powerful giant worm which can kill in one shot both Tarma, and it seems to me that you re supposed to spam Drill Slug, that have a too long recharge time.

Can anybody hint me on the strategy to use?

(The only thing I found on internet is to use Sand Bag and Drill Slug at the first wave to try to kill the more maggot possible, but past this point, I usually have maggot + giant worm breaching the sand bag, kill Drill Slug and my base before being able to respawn Drill Slug, both Tarma get killed before being able to use the shotgun).