No one but Lois was paying attention to Clark. If he was at full speed, he might be able to pull off a save with only Lois finding out. He could step away from her and fly off, changing in mid-air, and grab Lex. If he has enough time, he could zip around the corner before he changes so that it's less likely that anyone will notice that he came from the crowd, but he might not think of that.
I don't remember Clark ever doing a speed-change mid-air on the show, but that has been a regular in his repertoir in other portrayals.
