Irene's perfectly prepared to be revalatory- she is of the opinion that she has less to lose than Steph.

"Well, I could help," she says breezily, waving a hand, making it sound as if it's an offer of no consequence. She takes another drink- "Mm. Bit too much lime. Anyway- I know how these things go. And I'm not bad at..." She pauses for effect, giving Steph a half-smile. "Finding things out, shall we say?"

There; could be a playful offer, or it could be serious. It could even be a threat. At the moment, even Irene doesn't quite know which she's going for- Steph's/Sarah's response will solidify her purposes. It's always best to let someone else commit themselves before you do.