Think it's generally accepted that the aliens won't attack androids unless they're attacked first or the android directly interferes in any way (e.g if Bishop had attempted to remove eggs from the hive as some have speculated he did, it would have ended badly for him).
As for Ash, I suspect he would have left the alien to its own devices, maybe tried to seal it in somewhere it couldn't get out from, to make life a bit easier for the poor buggers who'd have to deal with it when the Nostromo arrived back at home?
