How do you take cover in such situations if you're surrounded on all sides and the enemy is in almost melee range?
Hide in ship. Bomb them into oblivion.
Enemy counts here pretty much mean nothing except the lag. There can be a few dangerous guys, like rocketeers / minigunners, but overall next to no resistance. And to top it off, there's no snipers IIRC, so you go at night and just enjoy the massacre.
https://www.youtube.com/watch?v=r9mYBlK-JJI&t=1380 (https://www.youtube.com/watch?v=r9mYBlK-JJI&t=1380)
As for lags, opengl /w raw filter should get you max game/scrolling speed at all times.
This mission is fairly benevolent as much as high-count ones go. Cyberweb late stages are a chore, and so are couple of others (MiB lunar is nuts).