Mark was supposed to be gone in a 13-0 Vote. But, hours before his eviction Ika asked (confronted) Mark saying if Cass said that Ika & Gary were the ones plotting his demise ((like the villain role)). Mark was like in the moment and said "yeah..." leading to Ika/Gary getting mad, going off on Cass, and calling a house meeting. Mark then managed to almost rally the votes to keep him in a 7/6 vote [thanks to Dallas (?) ] because of that.
Aftermath : The veterans are now against Cassandra due to this, but Mark even admitted that it wasn't true, and that Ika scared him. Lol so yeah - Mark fucked over Cass. #BBCAN5
Edit - and Sidenote:
• Cass also spoke about backdooring Neda (won't be able to happen anymore due to the Timewarp Twist).
• Cass spoke to Ika about Neda as well; Neda #maybe jealous of her because Cass was seen as the "most strategic" just like her last season, and Cass questioned why the public would award Neda the Timewarp and not her. Ika obviously then spilled the beans to Neda.