In order to kill yourself with electricity you need to acquire a shock
by passing sufficient current through your body, preferably on a route
that takes it past your heart.  Ideally, touch the live terminal with
one hand and earth the other hand, or a foot.  This way the current
passes the heart and you should be successful.

My immediate thought about Mrs. Tuttle's survival is that there was not
a connection between the supply and the water in the first place.  The
extension chords may have been submerged in 2.5 inches of water but if
the terminals at each end were still above water level the water will be
isolated from the electricity.

If the water rose to a point level with the terminals in either the
supply socket or the appliance then the supply breaker or fuse would
probably open.  All houses should ideally be fitted with an earth
leakage breaker which opens when a current of between 30 and 50
milliamps flows between live and earth, or alternatively a standard fuse
or MCB would blow due to the current flow between the live and neutral
when the water gets to that level.

If, as seems unlikely, the water was really at mains potential without
having blown a fuse or opened a breaker, it is still possible to stand
in it without getting a shock, although I wouldn't like to try this!
As long as all contact points on your body are at the same electrical
potential no current can flow so no shock will be felt.  Jumping into a
pool of electrified water is OK as long as you don't touch anything at a
different potential, such as an earthed switch or socket.  This is the
reason birds don't fry when they land on overhead electrical cables.
Any experiments are done at the individual's own risk.

Kind regards from where electricity is the correct voltage and
frequency,

Nicholas Simons.