damn safe modes and radio codes

[urmm]

went to the dealer, got the code
but they couldnt put it in because it was in safe mode.
Ive been asked to wait for an hour with the ignition on
im afraid with the keys in ssat maybe gone
Is there another way of getting out of safe mode
so i can put in the darn radio code

Need radio because ive got a 2 hour journey with nagging wife and 3 screaming munchkins
its a gamma

Cheers