So Arsenal will Rather fight for a draw than loose because if they draw they will be on four points and still remain second position in the group which will still be considered fair for them and keep them hopeful to make it pass the group stage, this is UCL and only the best is what teams give out and so I'm very sure if arsenal should be giving only but their best then Sevilla doesn't stand a place then because Arsenals best is way beyond Sevilla's best.
Arsenal will qualify first in Group B. Lens won vs Arsenal but they aren't fit to keep winning in my opinion. Their results in Ligue 1 aren't good at all also. PSV Eindhoven is a good team but with lower quality than Arsenal. Sevilla are good too but not that good to end first in my opinion.
Arsenal first, Sevilla second for me and if Lens could keep good results, they might pick the second spot.
I think Arsenal is in the luckiest group because the other 3 teams are weaker than them. I still think about how they lost to Lens. Lens are in a bad situation in League 1, but we can also say that they are fully concentrating on the UCL. They are currently leaders in the group with 4 points from 2 matches.