First bad gas can indeed clog just one or two or three injectors and .. Well the longer you run with it the more get clogged.
Second. multiply ways to drain the tank
Assuming you have a B.I.R.D. (bi-directional isolator device) you can simply plug in to keep battery charged. Disconnect fuel line at the filter and turn key to ON. firing up the in-tank fuel pump and let it drain off. Disposal of haz-mat (Gasoline) is up to you. I'd suggest a 'flash pan" and burn it But only if you are in an area where you can do that safely and without angering the fire gods (Law enforcement). Major danger in doing that if you don't know how (IE The other fire gods. Plastic Surgeons been there done that not fun)
|Or a siphon hose.. or both.
Then fill and treat to clean up remaining gas.
DOn't forget to change the fuel filter for if the gas is bad.. SO IS THE FILTER.