Player crit on a juvenile boar while it was on its wounded 2 ferocity stage. Should I have called it dead to keep the critical from feeling stale or was marking the third wounded level and letting the next successful attack end the beast the best option?

I did the latter and it did not result in a happy session where the rules made everyone feel treated fairly. Is a level 0 creature against two level twos supposed to feel this stressful? No one died though so...

Edit: thanks everyone. The support felt nice. I am glad this was just a one shot where me and the player were effing about with some weird builds. Feel like in a session with a full troupe I would 'rule of cool' this situation and have the pig prone after the attack at least.