Given tex (Complex environment):
  \begin{complexenvironment}[option1,
    option2]{first extra argument}
    {second extra
    argument}
    Hello world!
  \end{complexenvironment}

Do (Delete inner):
  die

Expect tex (Inner deleted):
  \begin{complexenvironment}[option1,
    option2]{first extra argument}
    {second extra
    argument}
  \end{complexenvironment}

Do (Delete outer):
  dae

Expect tex (Outer deleted):