«ما أنا رأيت أحدا»
I did not see anyone.
«ما أنا ضربت إلا زيدا»
I struck none except Zayd.
The first sentence denies an act of seeing by the speaker; it does not establish that someone else saw people. The second contains illā (إلا), which introduces a distinct exclusion/restriction pattern. That restriction must not be projected onto every clause that starts with an initial pronoun.
Some combinations are rhetorically awkward under a particular exclusive interpretation because subsequent total negation clashes with the supposed contrast. Proper interpretation begins by identifying exactly which action and which participant are being denied.