Smiths Medical Software Engineer interview questions

The interview was fairly protracted in length - over 3.5 hours and all of it in one room after a very brief walk-around. Most of the questioning was quite friendly and positive, that is until near the end. One older man whose name eludes me (and I wouldn't state it even if I did recall), who came in at the very end, decided to insist that I answer how I would architect data structures and implement the C code needed to realize a notepad-type editor. He literally said he wanted me to write code verbally, on the spot, with no time to really think anything through and while he was shooting holes in what I did have to say as I went. I found that tactic infuriating and inappropriate (and that's what I told the recruiter afterwards) - no SE develops code with 5 min. of explanation of the project and is prepared to present his/her ideas literally minutes after the project's is described. He may have been trying to assess how I handled pressure, but this was ridiculous and turned me off to the whole opportunity. The person came across as arrogant and confrontational at times.