Question

How a cell can end up with mutiple nuclei

Answer 1

Those are binuclei cells, like muscle cells or skeleton cells. They have them because they aren't really one cell. They are more fusion of multiple cells.

Answer 2

A cell can end up in two nuclei because of a genetic defect, problems while the cell is reproducing or like live cells which have 2 nuclei because they have more task to do.