In Night, what is ironic about the warnings of the electric fence, that Elie mentions?

The warnings of the electric fence surrounding the
concentration camp are ironic because the fence is certain death to any prisoners who
try to surmount it. However, the fence is ironic because it also represents a means of
escape and freedom. Furthermore, Wiesel mentions that it's funny they bothered to put up
warning signs about the fence when death was lurking around every corner. It was odd
that SS officers bothered to warn prisoners of electrocution when they were killing them
off in masses anyway and enjoying every minute of it.