Just a few seconds before the pickup, we see the other ambulance being shot at up at the other end of the street.

Then we see the ambulance under discussion pull up to the right of the cameraman, having been out of the shot during most of the action. We can't see the driver, except for a brief second while he checks as he backs up. We don't know if this is the ambulance's UN driver or if the ambulance had been hijacked prior to the pickup. We don't know if there is a passenger in the front seat, nor whether the passenger is a UN worker or one of the many, many fighters who appear in the clip. We do know that a lot of heavily armed men have gotten into the ambulance.

We also have some inkling that the cameraman is being allowed to film all this by the fighters.