Specific use of Present Continuous

Question

Could anyone please clarify this specific use of the Present Continuous for me? The following two excerpts are taken from movies:

1) Malcolm in the Middle

He's giving that same lecture to younger classmen. I can't let that happen. I'm stealing his slides.

2) Groundhog Day

[Phil has been brought to a hotel by his manager]

Phil: I hate this place. I stayed here two years ago. I was miserable. It's a fleabag. I'm not staying here.

This doesn't seem to me like a future arrangement. It's more likely a spontaneous decision. Shouldn't Future Simple be used there instead: I will steal his slides; I will not stay here.

Answer 1

In both cases the present tense is associated with an announcement of intent, is confusing to people learning the language, defies analysis with the simple tools taught to beginners, and is idiomatic in both American and British Englishes.

The first form is a statement that, in effect, “I am now executing a plan to steal his slides”. It’s effective because it’s a statement of intent, with immediacy ­— they are going to steal those slides right now, or at least as soon as they can. It reflects the thought process of the person, where — in their mind at least — the stated action has already begun.

The second can be interpreted as of now, my being here is only temporary. Really there’s nothing surprising: a question-and-answer might go —

Are you here for the night?
Yes, I’m staying here.

where the action has already begun (he’s been staying since he arrived, and will be until he leaves).

In your example, Phil is simply stating the opposite —

No, I'm not staying here. I’m only here until you arrange something different or I leave to look for somewhere else.

In other words, neither of these cases is really about a future action at all, at least not in the sense of “planning” to do something.