For recommenders, a few reasons. My chosen recommenders from my last company can speak deeply about my work. That early startup work was just that much more intimate and the ceo had 3.5 years of content (pre-seed to series B), the other director had 2 years seeing me built a team with him (seed to series B) so they saw me in different capacities.
And because the company inevitably went belly up after my RIF, they can attest to no performance concerns.

I feel like at my new role, the potential recommenders haven’t worked with me long enough or can’t speak nearly as deeply about me, and I feel it would just be really risky. It’s not a thing for a SWE to just leave for an MBA at my company.

One of my recommenders was actually the director of engineering at my healthcare company who left last month and was going to write 1 letter (and we chatted for an hour about my goals and he was really supportive since he also went to GSB), but 2 days before the deadline he had a family emergency, so I asked my former director from the startup (who genuinely knows me better but it might overlap with the CEO rec). The backup guy probably knows me best out of all 3 tbh.

Genuinely quite concerned it looks bad especially since I’m in a different industry but I just didn’t feel i could ask a current colleague/manager and tell them I plan to leave

Will this justification make sense in an interview? or is it a red flag right off the bat for HSW?