Maybe Atletico Madrid have made a really good progress to secure their position in top four but I don't think they are very safe now. The balances can change anytime depending on how good Real Sociedad and Betis will be in the rest of the season. But after watching Real Sociedad for many weeks I have lost my belief in them significantly to catch up with Atletico Madrid. It started to seem like Atletico Madrid will secure the third position for themselves and the last position for the Champions League will be between Real Sociedad and Betis.
About the last position I'm favouring Betis. I think they have more potential than Real Sociedad if they keep up a decent form. It is easy to close a gap of three points for them in that case.
IMO they are totally safe
ATM is one of the best teams in Europe now quality-wise. It's a shame they were so bad pre-WC.