Re: "my suspension of disbelief finally broke"
...at a lizard lady doing something improbable with her oxygen supply? How do you cope with the frequently killed immortal, who travels around in an extra-dimensional, time-hopping police box from the 1960s? Doctor Who isn't exactly "hard" sci-fi.
Until we all learn to stop viewing homosexuality as a deviant behaviour, any incidence of such behaviour in any TV show is probably going to seem jarring and shoe-horned in*. The Kirk/Uhura kiss probably felt like that to many viewers, way back when, but I doubt anyone would bat an eyelid, now.
*I honestly don't care if the writers included it solely to piss-off the moral outrage brigade - if it helps demystify homosexuality among Who's intended audience, it served a useful purpose (it prompted a brief discussion between my young son and I, about same-sex marriage - of course, he thinks that kissing is icky, regardless of the participants' genders).