Hedda is repeatedly associated with fire, the stove, and burning stuff up. All the hints of fire in the first three acts lead up to the climax at the end of Act III, when Hedda burns Eilert’s manuscript and rants about "burning" Thea’s child. Look at all the times she sits by the stove: in Act I, she retreats to the stove when George wants her to look at his smelly old slippers; again when she converses with Thea; again when bantering with Brack; once more in Act IV shortly before she commits suicide. She’s all about her pistols, of course, which FIRE a bullet. When she imagines Eilert reading poetry, she visualizes him "all fiery" with vine leaves in his hair. Even George calls her feelings for him "a burning love" when he discovers she’s destroyed the manuscript.
We start to get a picture of burning discontent inside Hedda, despite her cool exterior. Clearly, she’s harboring some intense passion that rises to the surface every now and then. Notice that she feeds the fire after the night of Brack’s stag party – right before the scene in which she convinces Eilert to kill himself. Hedda’s games and intrigues are essentially feeding the fire she feels inside – the burning desire to escape the confines of her very stifled life.