Let's just imagine, hypothetically, for the the sake of brainstorming the issue that Imran Khan is assassinated in a suicide blast, like Benazir Bhutto. What would happen?
When Benazir Bhutto was killed there were riots around the country. A lot of damage was caused in Karachi, Lahore and elsewhere by PPP jialas.
Would it be any worse for Imran Khan? Most of his supporters are much more civilized than the junglee jialas of PPP. They may burn some cars and buses, but maybe not even as bad as PPP.
If it is foreign enemies who are behind the assassination, they will probably be happy to see as much destruction as possible. The local establishment may consider Benazir Bhutto level of destruction as acceptable.
PTI is a one-man-show to a large degree. With Imran Khan gone it may not last for long. For anti-PTI planners, foreign and local, it will be very tempting to get rid of him to gain complete control over the country.