succeeded in persuading me to stay where I was:

"The incline of the roof covered with lead plates," said he, "will render
it impossible for you to walk, indeed you will scarcely be able to stand
on your feet. It is true that the roof has seven or eight windows, but
they are all barred with iron, and you could not keep your footing near
them since they are far from the sides. Your ropes are useless, as you
will find nothing whereon to fasten them; and even if you did, a man
descending from such a height cannot reach the ground by himself. One of
you will therefore have to lower the two others one at a time as one
lowers a bucket or a bundle of wood, and he who does so will have to stay
behind and go back to his cell. Which of you three has a vocation for
this dangerous work of charity? And supposing that one of you is heroic
enough to do so, can you tell me on which side you are going to descend?
Not by the side towards the palace, for you would be seen; not by the
church, as you would find yourselves still shut up, and as to the court
side you surely would not think of it, for you would fall into the hands
of the 'arsenalotti' who are always going their rounds there. You have
only the canal side left, and where is your gondola to take you off? Not
having any such thing, you will be obliged to throw yourself in and
escape by swimming towards St. Appollonia, which you will reach in a
wretched condition, not knowing where to turn to next. You must remember
that the leads are slippery, and that if you were to fall into the canal,
considering the height of the fall and the shallowness of the water, you
would most certainly be killed if you could swim like sharks. You would
be crushed to death, for three or four feet of water are not sufficient
to counteract the effect of a fall from such a height. In short, the best
fate you can expect is to find yourselves on the ground with broken arms
and legs."