There will be many ways, but here is one.
Try drilling a hole in the pipe 6" inches above the concrete to see if the comb extends that far, try to see where the comb ends, you may need to drill a few holes, try drilling 3/8" and use a flashlight to see if u see comb.
Hopefully it doesn't go all the way to the bottom.
Then you can cut the pipe off with a torch, after cutting the pipe off, then quickly cover both ends.
Then make yourself a plunger, wrap rags around a broom handle until it slides snugly thru the pipe or cut the cover of a 5 gallon bucket so it just fits snide the pipe.
Put down a tarp or blue plastic and plunge it out to one end...........have a NUC Box or an 8 frame ready and salvage what you can
Bruce