She would check over the younger girl's work when it was through. It wasn't a lack of trust, she simply didn't know her and she wanted to be sure that everything was in order. Better to be safe than sorry, after all.
"Between Oliver, Clark, and a designed security system the building should be secure." Granted this Clark couldn't fly and she didn't know whether or not this Oliver was at the same skill level as her own Oliver, but if they were anything like the two she knew the building would be in good hands.
That settled in her mind, she thought it a good idea to bring up an encounter she'd had just the week before. "I was in a bank a few days ago when the Joker held it up. Very little good came out of it besides my being able to somewhat place him on a timeline. He's from a time when he and I are extremely well acquainted, but most importantly he said he hadn't seen me since the attack. That means he's from about two years ago for Diana and I.
"I'm worried, obviously because it's the Joker," she continued. "But also because Batman isn't here. The one he knows. He tends to get bored without Batman to 'play' with, and I don't know if the rest of you have ever experience the Joker's boredom, but a good deal of unnecessary death usually goes with it."