It alighted.
That’s what flying boats (mostly) do.

Why would an RFC fighter pilot necessarily have preferred a DH6 to an Avro?

In short – it’s very doubtful an RFC pilot (scout pilot OR artillery) would prefer a DH.6 to anything. They were unloved and I’d say the Avro would be a preferred option every time.

So it’s a fair question and I can’t think of a reason…

EDIT: unless it came down to cost or availability I guess.