Green’s Dictionary of Slang

get back v.

(US black) to think again.

[US]W. Safire What’s The Good Word? 79: This idealistic phrase [i.e. get down] should not be confused with to get off, ‘to achieve satisfaction,’ or to get back, ‘to reconsider’.

SE in slang uses

In exclamations

get back in(to) your box!

(orig. US) a general excl. of rebuke, be quiet! I don’t want to know! that’s quite enough of that!

[UK]Partridge DSUE (1984) 456/2: —1893.
[UK]Guardian 4 Nov. 🌐 If you listen to Ligeti and James Macmillan then why would you want to know who won the United game last night or which Cabernet Sauvignon to drink with your meal tonight? Get back into your box.
This is Hertfordshire 5 May 🌐 ‘When was the last time you had a vote?’ he shouted, to which Mr Ward lashed back: ‘Get back in your box, you freak!’.