You are going to need to alert a vehicle that has sufficent space, alternatively use the debug tool to delete them, or injure the personel and transport them away in a ambulance. For the green arrow, if you hold CTRL while alerting, it will not show up.
Ahhh i totally forget ctrl is the solution to the arrow although i frequently use the function lol.
I only find doctors & chief doctor (LNA) can be transported by RTW or KTW and doctor from GRTW can be transported by another GRTW. All other personnel cannot get on other vehicles even if ELW/LF/MTW(BF), RTW/GRTW/GW-SAN or GefTrFzg have extra seats. I'll try the debug tool next time.
Thank you for the advice!