Hmm i'd say there were signs from early on that Lena is treating it more than just a random hookup (both in her internal monologues and dialogues with Mike) but yes, a lack of option to avoid it is rather railroading. Then again, some other paths are like this (Lena not being able to take Louise's feelings seriously, Ian being pretty much limited to lovey-dovey path with Holly) so i suppose this boils down to amount of time/resources available.There must be an option that Lena is considering this casually and don't make a big deal. We may not be angry with Ivy, but in the case of Mike, Lena becomes braindead, although before that there were no symptoms that she was obsessed with him. This is more of a forced drama by Eva.