This is the last level of the game, and the trophy is not missable. Beat the level and it's yours. Keep in mind that there are two other trophies for this level, one for killing 20 enemies and still succeeding, and one for never being seen.
If you're playing on easy, it won't be that hard to just get the first one immediately, but note you'll need to kill the enemies within ~3.5 minutes once you're seen outside of the building. If you're playing on normal/hard, I'd recommend just beating the level as best as you can first so you can learn the layout before trying for the trophies.