Suppose the life insured has more than one surgery of the type listed. What happens then?

The benefit will be payable only once to any one life. If the life insured again undergoes any surgery whatsoever, no benefit will be payable even if the later surgery was of a different type from the first surgery for which benefit was paid.
Likewise, the benefit will be payable only once under any policy. This means that under Joint Life or Jeevan Saathi policies, or other policies under which there is more than one life insured, if any accelerated benefit has been paid in respect of one life, then neither life insured will be eligible for any future surgical benefit.