Loved that episode too.
I agree with MikeD, I think the bad guy has been already to the future, if I'm not mistaken he showed Lucy her diary (in the pilot episode) and Lucy said I haven't written that, bad guy said not yet, so he implied that he already went to the future and that's how he was able to secure that diary.
i hope this show stays good.
So far I like it, I enjoyed the plot, I like the fact that they sent Lucy with money so she could go shopping, very convenient when traveling to the past.

The Time Tunnel guys from the 70's would have loved that for sure.
This time travel assignment would seem like an easy job, punch in at 9 to travel to the past, be back at home at dinner time in the present, except that maybe the present has changed by the time you get back, just like Lucy came back and found she had no sister, and she's now engaged,
I'd like to see an episode where they send the trio to the Titanic, maybe they could save some lives, even at the cost of changing history.