With hose off pedal should have been hard as a rock, worse than an old
car with manual brakes.  When booster really goes bad pedal gets hard,
same as hose off.  It is possible that because the pedal went to the floor
the booster was damaged, very slight possibility, but possible none the
less.
you left out important info, like is there fluid in the master cylinder
reservoir,
is one end empty and if so which end?  have you looked at the wheels,
especially the inside of the rear ones for signs of leakage(blown wheel
cylinders
tend to soak the wheel/tire). also if it was low, but no signs of leakage at
wheels
look at the booster below the master, if the master has been leaking out the
back
it runs down the booster and the paint goes to snot. also unbolt master from
booster and pull foreword, look for leakage on back side. If its been
leaking
long enough it will build up in the booster and can damage the diaphragm.
This is more of a problem on Hondas and other ricers  as they use a natural
rubber diaphragm, and Honda says master leak, replace booster. sooo
much fun to do on an Accord, not.
Whitelightning