Mal didn't make it clear if he was outright ignoring Zoe's glare or if his trained eye on Book made it impossible for him to take note of anything but the preacher sitting on the curb. Mal's own gaze still teetered somewhere between shock and suspicion and Zoe had just cause to feel slighted that Wash's return had been accepted as easily. And if asked, Mal would have no explanation to offer -- as Mal wouldn't get into his feeling of responsibility even with his second in command. This one was a little too close.
"This place seems to be full of chances." The captain left his statement vague. Simon had found a chance at the life he felt he was owed. Kaylee had a chance to do whatever she did with Kyle or that fellow with the penchant for black leather, Wash and Zoe had the ultimate chance to renew their marriage. Chances for the browncoat Captain, however, seemed to have run out. He had a scattered crew and a ship that wouldn't so much as get an engine roaring, nevermind get off the ground.
"Got Serenity, not but a walk from here. Or possibly more now with the way the streets like to tangle themselves up when you're aimin' to get somewhere. Looking for board or you gone and find yourself a higher calling somewhere else in the City? Wouldn't be the first." Perhaps the Doctor's desertion was weighing heavier on the Captain than he'd admit.