Before the prison break, Ash had met Ronald alone in the cafeteria once.
Although Ronald was just a tool-man to him, it would be false to say Ash had no sympathy at all, so Ash had probed Ronald's plans after the prison break, whether to part ways with Lanna or to assassinate him.
If it was the latter, Ash could reach a certain agreement with him — no matter what, after fulfilling Harvey's contract, the escapees would definitely fight a battle first.
It was not about interests, nor was it about grudges, but purely a matter of trust.
You can't be sure whether others will harm you, so you must strike first.
When dealing with a group of death row prisoners who crawled out of a cesspit, it was right to think of them in the worst and most filthy way, because they too judged the good with a filthy heart.