Every technical leader eventually faces a situation where time is short and the system is unclear. An outage under investigation. A proposed architecture being reviewed. A board asking for a risk assessment. The question is always the same: where do you start, and how do you move through a system fast enough to be useful?
The decision here is not about a particular technology or team. It is about method. The complete mental map is the answer to “how do I think about any system, in any context, under any time pressure?”