I would perhaps try this:

if (system(qw/vp -e/, $ENV{VREL}) != 0) {
    # last command failed
    system(qw/vscmd set-measure-mode fast/);
    system(qw/vscmd pg-address-check off/);
}
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I'm not sure which program gets the ctrl-C, but if it's not the Perl script, that should work.