If FD isn't alreay rolling, get FD rolling.
my former FD's ambulance has SCBA's on it for this reason (and others).
If I was on this call with the squad, I'm not sure what I'd do. One potential idea would be for ME to go in wearing a NRBM (and 100% O2) and at the least open the garage door and shut the car off... That wouldn't be perfect, but it would be "doing something" rather than sitting around for 10 minutes waiting for the FD to respond and arrive and watching the guy die.
Also... PD might just be dumb enough to bring the guy out for us
Finially... I'd also request PD when I request FD, because we have a potential EDP with a suicide attempt... once they cease being hypoxic, they might become combative.