When confronted with a 3 piece maneuver I try to plant the new part on a handy place instead, keeping it 2 parts always;
I’d have attached the small module sideways on “top” and plucked the part for the bottom and placed that then turned the top part the right way
I just quicksave and hope for the best. Usually, if a module drifts off into space, as long as it has engines or rcs, you can always bring it back. If it doesn’t, you can always send a drone to carry it back. Unless, of course, you’ll be doing some major time warping, in which case it will probably end up on a completely different orbit.