Discovery. Polera v. Wade
In Polera v. Wade (Ont CA, 2015) the Court of Appeal affirmed the point that once a party introduces at trial evidence drawn from discovery that the entire discovery content becomes available to all parties for similar use in evidence:
 First, the motions judge was entitled to consider Ms. Polera’s impugned discovery evidence. Once the appellant relied on her discovery evidence, he opened up its use to both parties. As a result, the motions judge was entitled to consider it for all issues.
 On this point, we agree with the analysis of D.M. Brown J. (as he then was) in Lawless v. Anderson, 2010 ONSC 2723 (CanLII), 188 A.C.W.S. (3d) 1006, at para. 12, aff’d on other grounds, 2011 ONCA 102 (CanLII), 276 O.A.C. 75:
As a general rule when a party places into evidence answers given by an opposite party on her examination for discovery, such evidence is available to either party in the same manner as any other evidence.