Pardon is followed by doing, because the subject of this sentence is you, and ellipsis is because ellipsis will not produce ambiguity. And do, namely disturbing, its logical subject is I, which is different from the subject of the sentence, so a logical subject should be added after disturbing. Logical subjects can be nominative, accusative, possessive pronoun and noun possessive case. Obviously, the logical subject of this sentence is an adjective possessive pronoun.