1
Season 1 Ep.17. [ 3 min. 40 sec ] Jack & Dal talk to Lex. Lex is to be married today. (1st wedding to Zandra, later to be aborted). He reminds Dal he should be on guard duty. Jack probes his intentions re. Zandra. Lex declares that for him, the ceremony means nothing. Jack recalls an earlier conversation with Ryan. Lex knows what Jack is referring to. But the truth is, whatever he might have promised Ryan, that Tai-San will not be conducting a "proper" ceremony, so he will be free to dump Zandra at any time. But don't tell Zandra.!
2
[ 12 min. 40 sec ] Lex and Ryan are in the sewers while Jack and Dal fix a faulty alarm system. Ryan cares for Zandra, and doesn't want to see her get hurt. He asks Lex if he loves her - really, really loves her. Lex promises Ryan that he does.
3
[ 16 min. 20 sec ] Jack & Dal get talking to Ryan about his best-man's speech. He's going to say "How pleased I am for her". Dal can't believe it. Ryan understand Dal's misgivings about Lex. "Lex has promised me he'll look after her and be a good husband." Jack can't quite believe it either.
3 had to happen after 2 (which it does). 1 can only happen AFTER 3. Except is doesn't.