I think your installation is hosed anyway. If it's asking for disk 2, but the OS thinks disk 1 is still in use, something's up . . .
FWIW, I also hate the way OSX controls this. Not having an eject button is just aesthetics. If the OS isn't clever enough to be able to get it right (and it's not, ejecting a stuck disk is a regular topic on these forums) they should let us do it ourselves.