I think that this whole thing about getting the who, what, where out in the first few lines is a scene killer. It may be this necessary building block for newbies, but when two moderately experienced improvisors are worrying about that stuff at the opening moments of a scene, it can be dreadful to watch and dreadful to do.
One solution that I’ve advocated for years is just do something, anything at the beginning of the scene. Don’t think about it, don’t talk about it, don’t make the scene about that activity. Just do that thing so that your scene partner can join you and you can blow past the who, what and where. Start talking about anything else. This tends to work reasonably well.
But when you can do that, there is a whole different set of muscles to work on. They are acting muscles. You should be able to answer a bunch of questions in the beginning moments of a scene. How do I feel? What is my partners behavior? How do they feel? Do I like it? How do I feel in response? What do I want from my partner (in terms of behavior)? I like scenes where there is a whole dialog between the players not in words, but in behavior and emotional responses.
I wish a lot more of my scenes started that way, where I can ignore the who, what and where and simply concentrate on the how. How is my scene partner behaving? How do I feel in response? How far away from me are they? How fast is the tempo of this scene? How is my body shaped? How am I using the stage and the architecture of the space? When I focus on these things, the why comes automatically and the who, what and where just tumble out on their own, as if there were there all along.