He IS a lousy liar, but I thought it was very Bill-like to try and lie to her. Perhaps he got a quick lesson here in why that's not a good idea--she sees through it. But he sort of got validated for trying to make her feel better (she thanks him anyway) which might help explain why he still loves the pointless gesture--like making Kat CAG before she dies. While I do see that that sort of thing gives some people comfort, I really don't think it works for everyone.
The actor's doing really well, I think. He's obviously studied EJO's delivery and intonation because his 'battle' voice was uncannily accurate. Also: blue eyes! Wow, are they blue. :) I liked his moment of focussing before launching (as he watches JC carried away). It was very Lee-like to take that reflection moment but his attitude coming out of it was all Bill. I don't think Lee would vocalise quite the same way. 'Let's do this' almost made me laugh, it was so melodramatic--you can see the slow-clapper that he'll become showing there. ;)
In other ways I thought there were a lot of similarities with Lee--especially in the third flashback. Something in the precision of his 'break left on my mark' was very Lee, even though his voice sounded totally like EJO. He was very focussed under pressure and he had a hard edge to him, even despite (or because of) what he'd just seen. His response to shooting down his first toaster was pretty restrained, which I thought was interesting--it sets him apart early on from typical hot-headed pilots eager for combat. I also thought it set up nicely his response to seeing the Columbia destroyed because it provided a contrast: it's that that really leaves him shocked and he quickly finds a focus for this, ignoring his CAG's orders. He gets reckless and that reminded me of Lee who've we've seen at his most 'showy' and aggressive when he's got nothing left to lose.
In the light of much discussion about Lee and heroism, the line 'Don't be a hero, Adama!' was meta heaven. Yup, once again the issue of the thin line between heroism and stupidity/endangering a mission comes up again. Yay! It seemed totally characteristic of Bill to pay no heed to that warning, and again there were echoes of his son too in the way he talked to himself, but whereas Lee has to talk himself into or out of situations, in Bill it sounded more like bullish determination, less insecurity.