They entered together (kata to auto eiselthein). Like epi to auto in Act 3:1. The infinitive eiselthein is the subject of egeneto.
So spake that (lalēsai houtōs hōste). Infinitive again parallel to eiselthein. With the result that, actual result here stated with hōste and the aorist infinitive pisteusai (Robertson, Grammar, pp. 999f.) rather than hōste and the indicative like Joh 3:16. It was a tremendous first meeting.