How to execute 2 commands inside a single runas?

1. When executed independently, they execute perfectly.
2. When executed in 2 consecutive runas statements, chrome.exe is executed before robocopy has had a chance to finish.
3. When placed inside a single runas separated by a &, it will not execute properly. Why?

 runas /savecred /user:chrome "robocopy C:\Users\chrome\AppData\Local\Google\Chrome-Backup C:\Users\chrome\AppData\Local\Google\Chrome /mir & \"!ProgramFiles(x86)!\Google\Chrome\Application\chrome.exe\""