Learn Spanish (Latin America): Me molesta que ustedes terminen empapando la sala. - It bothers me that you guys end up soaking the living room.

The structure terminar + gerund (words ending in -ando or -iendo) expresses 'to end up doing something'. Therefore, terminen empapando translates perfectly to 'end up soaking'. If you used terminar de + infinitive (terminen de empapar), it would change the meaning to 'finish soaking', which isn't what we want to say here.

Why is terminar conjugated as terminen instead of terminan?

Terminen is in the present subjunctive mood. It is triggered by Me molesta que (It bothers me that). Whenever you express an emotion, reaction, or value judgment about what a different subject is doing, Spanish requires the subjunctive for that second verb.

Could I use acabar instead of terminar in this sentence?

Yes, absolutely! When talking about how things 'end up', terminar and acabar are completely interchangeable. You could easily say que ustedes acaben empapando la sala and it would mean the exact same thing.

Why does the sentence start with Me molesta instead of Yo molesto?