In a life-critical application using an interpreted/VM language, you don't just want to ensure the correctness of your own code. You also have to ensure the correctness of the interpreter/virtual machine. In the case of Perl, the internal code is so full of feaping creaturisim and hysterical raisins that verifying correctness is nearly impossible.

However, that does not mean that VMs in general are a bad idea for such an application. One can start by writing a VM with a stripped down set of opcodes which are designed so that the resulting programs are easy to verify. The VM need not be complex (complexity would only make the verification process harder) and can be integrated into a ROM chip (to borrow BrowserUK's idea).