Historically, those media contracts are negotiated prior to them expiring, the B1G media rights expire after the 2029/30 season.
Now the language on leaving has been a little more specific once I found the data published beyond the paywall. It's 200 million to depart this year, and that number goes down by 15 million per year until AFTER the 2029/30 season where it drops to 75 million.
Now, there's nothing posted about them agreeing to leave the conference before then and exiting only when the the big drop off happens and the B1G including those new markets in their negotiations though I'm sure there's language in there to protect against that specifically. It looks like they're just protecting themselves from B1G expansion based on media contracts--the B1G obviously can afford to help them by giving them smaller shares for a few years as well or just outright--and there's some allure to the likes of Florida State, NC, and Clemson.
I'm really curious how this will end up affecting the bottom line for the MWC/PAC negotiations if at all--because this is the opposite of what we've seen so far for negotiating lower costs to get out of conference affiliation.