Hmm.... Not really sure, but I guess you could try putting the G3 in Target Firewire mode [connect to MBP with firewire cable, restart the G3, and hold 'T' (I think
) during boot], then insert the disk into the MBP, and when it tells you to select a disk/volume to install it on, just select the G3. Not 100% sure if that's gonna work, but it's probably worth a try. Hope that helps!
(p.s.: how'd you manage to break the disk drive?
)