Odo thinks about morphing into someone Bee'eef's species, in order to help subdue him, when he arrives and sees Bee'eef. A giant Bee'eef. Now way Odo is going to be able to morph into that.

This is when Bee'eef starts shooting. Odo morphs into a shield in order to protect his crewmates, or at least slow down the shots. If he cannot use his first plan maybe...

Once the shooting is over, Odo glances around to check no one is injured, then morphs into a falcon and aims at Bee'eef's eyes.