How close could people actually get? Close enough — the bridge filled up along its whole parapet, boats pushed out onto the water, and Turner was in one of them with a sketchbook while the river took the orange back up and doubled it. That was 1834, the furnaces under the Lords stoked with old tally sticks. The masons who raised what stands there now were at it for something like thirty years after.
Fabien, the engines that night were hand-pumped, and the tide was out, so crews had to run suction down the foreshore mud to find water at all. A floating engine came up the river eventually. Everything about getting water uphill from the Thames takes longer than you'd think.
Those tally sticks were Exchequer bookkeeping, notched elm, obsolete for years by then; the record shows the order was simply to get rid of them quietly, and the stove under the Lords seemed the tidy way to do it. Quietly didn't take.