Stephen Vassallo, aged 28, and 20-year-old Mark Sciortino also admitted causing more than Lm50 worth of damage.
The men also pleaded guilty to the charge of heroin possession and Vassallo admitted breaching the terms of a conditional discharge.
The court, presided over by magistrate Consuelo Scerri Herrera, is due to pass judgement next week. Inspector Yvette Farrugia prosecuted while Dr Victor Scerri and Dr Roberto Montalto appeared for the defence.