"where people put money into your account" here can mean "where people cause money to show up in your account by applying for a loan in your name".

The constrained message length and lack of edit feature on Twitter means you have to forgive people if their wording isn't exactly as accurate as you might want it to be.

Bob doesn't have any of the original details of the originating bank and loan, he's sufficiently likely to trust the person who seems to know what's going on and who messaged him out of the blue, saying "Please, please, I beg you, transfer the money that just showed up in your account [from Loaning Bank] back to me, at Different Bank by means of Western Union." Bob, being a kind and honest person, is unlikely to guess at the existence of the loan.

If the person does look up the details and just transfers the money back to the loaning bank, that doesn't cost the scammer anything.

If Bob has his antannae up he does. If not he sends it to the IBAN that the scammed gave him for the 'return' payment.