When budgies regurgitate, the seed doesn't scatter everywhere and just falls off to the floor. Regurgitated seed is all clumped together (many seed joined together by saliva).
When a budgie vomits, the head moves sideways while seed comes shooting out of the beak in a more violent manner, the seed is loose and can be found scattered in all different places. When inside the cage, the vomited seed is found in some parts of the cage bars as well as other places.
From your description it seems your budgie has vomited. Do keep an eye on Buddy for signs of lethargy/puffed up feathers and/or decrease in appetite.
If he keeps on vomiting, then a visit to the avian vet is in order.
I hope Buddy feels better soon, good luck.