In the terms of extroverted thinking the stipulation might sound something like, "Yo, so it turns out people make decisions for all sorts of reasons, and some of them subjective, but whether logical or felt, these decisions are part of the environment now!" It'd make sense then as an extroverted thinker to start an investigation. Maybe squeeze some feelers and see what comes out. The idea then is not to mimic them.
The stipulation about decisions in the environment applies to your own decisions too. So, adding together what you've seen others do (and asked questions about to learn "the truth") and comparing it with what you know of your own states and events, you might start seeing where you differ and where you're the same, and maybe invent your own metric. Voila, conscious Fi.