I wouldn't think TEE is really so "random" - there are always a few questions on the ITE identifying structures (basic, like chambers and valves) and coronary distributions. The ABA wants you to know this and it is a potential station on the upcoming (obnoxious) OSCE stations they will start in March of next year.
Yeah, lucky me, I'm the first one through for the OSCE. Not really saying TEE is random per se, more like it's a little off the beaten path and will almost certainly get a few questions on it