For Quine programs one is not allowed to read the source of the program, for obvious reasons.
However Del|m|t does a good deal of memory storage in the source code of the program, thus it can read and write to its own source while it is running. Del|m|t can even write out of bounds by writing to negative indices you can create extra memory. What counts as reading the source code for Del|m|t? Can you read in the negative space before the source code or are you never allowed to read from the "source"?
TL;DR: using command 20 on a value >= 0 counts as reading your source code.
Del|m|t puts the program's executable source code in the storage, starting from index 0. That means only non-negative storage spaces count as source code, as the negative ones do not store characters of the source code.