You have an electronic throttle, no cable starting in 1999. But this is not a Toyota, Volvos have brakes and she can always shift to N if there is a problem.

If it only happens at cold start, I would clean the throttle body. The ECT is asking for more fuel at initial start because it knows it is a cold engine. Of course, if there is a leaking fuel pressure regulator or anything else that is leaking fuel into the manifold, that would also cause high rpms.

If the rpms go down after a few seconds after start, like 10-15 seconds of 2500 rpm, then clean the throttle body.

Klaus