Pretty laid back although some interviewees felt it was kind of nerve wrecking.
I believe I was the only one with 2 interviewers that day for whatever reason, but the 2nd interviewer made it so much more comfortable because she was cracking jokes and was really enthustiastic.
You’ll be fine as long as you present them with your passion and a personable personality.
Be prepared for ethical questions and group dynamic situational questions.
Heard back yesterday that they accepted me in their OTD cohort, along with 3 other interviewees I made friends with that day. There could have been more accepted in the OTD as well (there were 12 of us total and I believe half was MSOT interviewees). They accept only 18 people for OTD while they accept 30 for MSOT, so DO YOUR VERY BEST.
Good luck! You’ll do great!