Marine structure to focus on as an alien?

As an alien what marine structure should you focus on destroying when assaulting a marine base? Depending on the circumstances of course some bases might be easier to take down say, for an example, that they've only got a Phase Gate so your first instinct is to focus on destroying that, not the Power Node, right? But what if they've got a large base with numerous structures such as a Armory, Arms Lab, Prototype Lab a Observatory as well as a Command Center and a Phase Gate. If you're a large group doing a coordinated attack on the base the general strategy is to just go for the Power Node which will effectively shut down the entire base. However, say that you're a single Onos or a duo of Skulks attacking this base what structure SHOULD you focus on? As in, what would benefit the team the most?

Thanks for any tips.