They're trying to force Nikki on the ticket. If Nikki is on the Ticket they will "Lee Harvey Oswald" Trump. It's a famous playbook
Theodore Roosevelt for McKinley
Coolidge for Harding
Truman for Roosevelt
LBJ for JFK
Nelson Rockefeller for Ford ("Squeaky" Fromme was a bad shot-twice)
George HW Bush for Reagan (Reagan lived but Bush still took over the govt)
Kamala for Biden (Kamala turned out to be too stupid)