At the same time as:
— The building collapsed just as he arrived.

synoniem: even as.

Roget 120: at the same time; simultaneously etc. adj.; together, in concert, during the same time; in the same breath; pari passu [Lat.]; in the interim; as one.    at the very moment etc. 113; just as, as soon as; meanwhile etc. (while) 106.    ... meer laten zien

Roget 17: as if, so to speak; as it were, as if it were; quasi, just as, veluti in speculum [Lat.].