Joe Biden, Nancy Pelosi, and Robert Byrd will be sleeping less comfortably from now on.
Line of succession:
1. Vice President
2. Speaker of the House
3. President Pro Tempore of the Senate
4. Secretary of State
5. Secretary of the Treasury
6. Secretary of Defense
7. Attorney General
8. Secretary of the Interior
9. Secretary of Agriculture
10. Secretary of Commerce
11. Secretary of Labor
12. Secretary of Health and Human Services
13. Secretary of Housing and Urban Development
14. Secretary of Transportation
15. Secretary of Energy
16. Secretary of Education
17. Secretary of Veterans Affairs
It would be too obvious for her to kill them all. Instead, she will have the Liberal Messiah martyred. Then she has Joe The New President make her the new Vice President (the Congress would quickly confirm her). President Biden, if he knows what's good for him, becomes a figurehead and Vice President Hillary Clinton would be the de facto President.