The word "there" indicates a point in space, and the word "then" indicates a point in time. Is there a word that indicates a point in spacetime, equal in meaning to "there and then"?
Immediate may be what you are looking for. Immediate carries the sense of both space and time.
Forthwith is another word (adverb) which means the same as immediately.
In physics, a point in space-time is known as an event.
(and a series of events is known as the world line)
My guess for a term which isn't jargon would be something like "spatiotemporal position" or "spatiotemporal coordinates". While I can't access its definition, "Temporospatial" also exists and is probably a synonym.
I don't think we have a word like that. I would rather use the phrase 'there and then', though I cannot think of a scenario where you would need that. Can you give me some more context here?
There can mean there, obviously.
There can also mean then:
5. ### a. At that point or stage in action, proceeding, speech, or thought; formerly sometimes referring to what immediately precedes or follows: at that juncture; on that; on that occasion; then. a1400 Relig. Pieces fr. Thornton MS. 77 At myn endynge..I pray þe lady helpe me þare. a1450 Le Morte Arth. 2388 The kynge Arthur Answerys thore Wordys that were kene and throo. a1450 Le Morte Arth. 3480 ‘A! false traytor’ he sayd thore. 1600 Shakespeare Merchant of Venice ii. viii. 46 And euen there his eye being big with teares, turning his face, he put his hand behind him. 1604 Shakespeare Hamlet ii. i. 19 And there put on him What forgeries you please. (OED)
Hence, there can mean there and then.