Use of や as "when"


In the fourth volume of 白銀のソードブレイカー I found an use of や that I think means
"when", similar to と, but I can't find this meaning in my grammars or on the
Internet; here's an example:

> ヴァリエガータの部屋にたどりつく **や** 、叩き壊さんばかりの勢いで襖を開けた

As I said, I think this や means "when", similar to:

> ヴァリエガータの部屋にたどりつく **と** 、叩き壊さんばかりの勢いで襖を開けた

Am I right? If so, what differences are implied in using や instead of と?




Maybe this is shorten expression of 「ヴァリエガータの部屋にたどりつくやいなや（…や否や）」 this means
"just sametime". Please see following for reference
<https://dictionary.goo.ne.jp/thsrs/17260/meaning/m0u/> 「たどりつくと」does not
contain meaning of sametime.




Maybe this is shorten expression of 「ヴァリエガータの部屋にたどりつくやいなや（…や否や）」 this means
"just sametime". Please see following for reference
<https://dictionary.goo.ne.jp/thsrs/17260/meaning/m0u/> 「たどりつくと」does not
contain meaning of sametime.

