Immediately/In the Moment
Immediately or “in-the-moment” refers to the snap judgement you make during a fight based on intangibles such as blade pressure, body movement, and perceived intent. In terms of cognitive psychology this would be considered 'automaticity' of action; judging the exact amount of brake to use entering a corner, or navigating through busy traffic are examples of acting "Indes" which demystify the concept.
The description of Index from the Liechtenauer glosses gives specifically the feeling in the bind as the epitome of Indes, implicitly linking the ideas of Fuhlen with reacting in the moment. Whether this connection between the two is necessary for an action to be described as Indes, or whether it is merely a useful exemplar, is a subject of debate amongst practitioners of 15th century fencing.
Meyer is more explicitly general with his use of Indes; it is the wider decision of what to do in the moment rather than a Fuhlen related concept.