I did think there were some implausible elements in this episode. First of all, Tae Sun was given only half an hour to get to where they told him to go, but in that half hour, it was supposedly enough time for all this other stuff to happen, in thirty minutes or less? I really can't buy that. :p
Finally, the last scene. While it did make for an awesome cliffhanger, it was really kind of ridiculous if you think about how it had to have been pulled off.
I love this drama, I loved this episode, but I think that this time they did kind of take an unrealistic detour from reality with the story in this episode.