Silentone...combat is never simple..in this case the party is being attacked by two types of enemies. So ponder which you feel is the most important for Ray to attack, Imps or rats. Now we saw that Ray was effective with the flame blade against the hord, do you think she needs to continue to protect the other party members while they destroy the Imps or help to destroy the Imp so that the hord will then disperse. The rats are slowed but they are still coming. It will take a couple of more rounds to defeat the Imps.
So as I said it isn't simple, but if Ray goes after the Imps she needs to use silver or + magic melee weapons so she would have to release the flame blade spell.
The bear could help some with the swarm of rats with three attackes of claw, claw ,bite but itwill take damage as they swarm over it. Depending on how Tann rolls it the claw hits might take out several rats at a time.
What does your gut tell you?