Is this safe for my beta fish?

So I’ve had beta fish in the past- I’ll just start out with that. I recently got a new one and his bowl is the generic vase with some rocks in the bottom, but I also put a shot glass in there (kind of a tradition, I set all my beta fish up this way and it’s fine). Everything is going great with him except I’m not sure what he’s doing right now.

I just got back to my room and he was diving as hard as he could into the shot glass. There was food in the bottom and I thought he was eating it so I managed to flip the shot glass over and dump the food out and put the shot glass upright so that the food was in the gravel but he’s still diving into the shot glass like he’s suicidal. He is coming up for air really really fast every now and then but he’s motionless with his face at the bottom of the shotglass for the most part. Should I just take the shot glass out? It’s kind of scaring me because I don’t want him to die but I have no idea what he’s doing.