And remember how Tommy reacted to finding out Josy was joining the HOTs, and when he thought the Jocks stole the girls for their party, and when Rusty said his Dad won't fund the DIKs anymore? These showed that he's brash, impulsive, and selfish, and he already perceives Josy as a threat to him having a good time, just imagine if he comes to perceive the MC as an even bigger threat to him, particularly to his position in the DIKs and his general easy-going life at B&R.
Since Ep 1 it's been clear that Tommy is an asshole and Ep 5 has now seemingly set him up to be at odds with the MC, so if this episode were to further that divide and he saw an opportunity to mess with the MC in a way that would have serious consequences for them, then I don't see why he wouldn't take it.