The actress, whose last scenes air on New Year's Day, said that her character's death is testament to her 25 years on Albert Square.
She told The Sun: "They didn't just want me to say ta-ta and get on the No 30 bus because that wouldn't do me justice.
"They wanted something dramatic, a fitting tribute to the character."
Referring to the departures of Barbara Windsor (Peggy Mitchell) and Wendy Richard (Pauline Fowler), St Clement said that it may spell the end of the EastEnders "matriarchs".
The 69-year-old added: "A trio of people all of the same age leaving does leave a gap. Who is next in the age line? There isn't anyone."
> Barbara Windsor, Patsy Palmer lead Pam St Clement EastEnders exit tributes
Watch a preview trailer for Pat's exit from EastEnders below: