BIBIGHAR - The Forgotten Massacre of 1857

[RanvirSena]

That might be motivation for the Sikhs who faced those sipahis in anglo-sikh wars and lost their kingdom, but i dont think Punjabi musalman and Pashtun had such grudge against Hindustanis of Delhi, Awadh, Rohilkhand, Jhansi etc. Gurkhas had no beef at all, they proved to be pure mercenaries

British recruited Eastern Rajputs from Bihar and Central UP known as Purbiyas meaning Easterners. They did not recruit from Delhi at that time.
Purbiya - Wikipedia, the free encyclopedia

When they entered Delhi many of them resorted rating and looting.